Interesting question. Here is a possible example: In Plato's Protagoras, Plato has Socrates and Protagoras argue about whether there is just a single virtue (despite the different names for virtues, such as "justice" and "courage" and "wisdom" and so on), or whether there are several different virtues, corresponding with the different names. So one might think that Plato decided to take up this topic, because he thought it was one that was controversial or under discussion at that time. To the best of my knowledge, however, no one believes in "the unity of the virtues" anymore. But even if there is someone out there who does, I think it might still be true to say that the view is not taken seriously by "most contemporary professional philosophers," as you put it. I'm sure there are other instances of "dead" theories, as well.
So let's start with the most obvious part: "philosophy" comes from the Greek "philo" (love) + "sophia" (wisdom). Whether what we do now is all rightly conceived as wisdom might be a matter of debate, but it seems highly likely that no one will be a good philosopher unles he or she really loves philosophy. Moreover, although I don't believe a good philosopher has to love all philosophy, I do think it is important that he or she loves at least a lot of it. This is partly because the best philosophy makes connections to other areas of philosophy, and often brings in sophistication from more than a single narrow area in application to problems within that area. The other reason why such love is critical, I believe, is that philosophy is hard. Solving philosophical problems is a rarity, to be honest, and even understanding some of the solutions others have offered can take a great deal of effort and patience. One who does not love philosophy will find all that effort and patience quite difficult to come by. Love allows one to be comfortable, happy, avoiding the shortcuts and wanting "the real deal" out of involvement in really difficult problems. But this kind of work can be frustrating, anomic, tedious, and at times can feel like progress is nowhere to be found. Only love, I think, can help one to push through such obstacles.
Other than love, I suppose I would also claim that good philosophers generally need to be quite intelligent in analytical ways (though, alas, we can often also plainly embody the "absent-minded professor" stereotypes in ways that can be embarrassing!), and it helps for one to be a good philosopher that one is genuinely open to criticism and a good listener. In my experience, there can be quite gifted philosophers who do not have these traits, but I always think they could get even more from their gifts if they had them. Some years ago, in my APA-Pacific presidential address, I actually argued that the virtue of modesty is one that would be very valuable to those who wish to be good philosophers. I still believe that, but never believed that all good philosophers were modest. Rather, I think that if a good philosopher were also modest, the virtue would make him or her an even better philosopher. But to be at least good, I'm afraid modesty is not required--instead, just being good at philosophy will generally be a matter of having the love and also having great analytical skills. But even these are not quite enough, because to be good at philosophy, the analytical skills also have to be accompanied by an ability to "think outside the box" and to consider solutions from angles that others have not imagined before. Just having good analytical skills does not always guarantee intellectual originality. That, too, is necessary for one to be good at philosophy.
I think the practice of "rating" different departments is tricky at best, and at worst sheer fraud. So my answer will be very indirect.
Obviously, students want professors who are engaging and interesting to teach them. But from a distance, I think it can be very difficult to assess whether either of the places you are looking at would be preferable on this score. The only access the general public has to student responses to teaching is something like ratemyprofessors.com, which I would use only with the most extreme caution. For one thing, it provide samples from only the tiniest fraction of students who have taken the professor--and only those who liked or disliked the professor so much that they wanted to put ion the effort of a review. Moreover, their editorial standards are quite lax--in my own case, there appears a crank response from a supposed student who says he/she took a course from me that does not exist in our curriculum, and the likes of which I was not teaching the term reported. I assume someone meant it as a joke, but you see what I mean. I did protest its appearance, but never got a response from those who run this site.
So I expect you would find this a dead end, but you might see if you could go and ask some current students howw they felt about classes they had taken and such.
I think, however there is another measure that you can pursue, and this will give you very good information--though, again, it will not tell you all you would like to know. Go to the department's web site, and look up the different professors. Here are some questions to ask when you look at them (and their CVs, if you can access these--most good departments these day encourage their faculty to provide these on-line, because they tell you all about the professional lives of faculty):
Are the areas taught ones you would find interesting? (And ask yourself--if you don't think you would be interested, why wouldn't you be? Beware of thinking you already know what you don't know!)
Is this professor active in his or her field in a way other than teaching, and to what degree? Good teachers are often good precisely because they are enthusiastic and engaged in what they teach. The best indication of continuing engagement in one's field is if one is publishing research in his or her field actively and regularly. People have a kind of stereotyping prejudice that "researchers" hate to teach and are bad at it. I think the truth of the matter actually works in reverse--researchers actually love to teach, because it is a great way for them to share what they love. That doesn't meean they love teaching every class they may be assigned, or every student that might wash up on their shores. But the ones who have ceased to love their field enough to want to contribute to it professionally are much more likely to be bad teachers, because they don't any more like what they are doing, but need the paycheck. So check out your professor's research record--if they aren't doing much in that venue, you can expect even less in the classroom, as a generality. And even if they might still give fun lectures, they are obviously not widely known or respected by others in their field, so if you want to go on to do post-graduate work (especially in philosophy), their letters won't count for much.
The other thing I would ask about is how big the class sizes are, in general. Larger classes for philosophy are almost always worse than smaller classes, because so much of philosophy gets done in discussion and active engagement. It is almost impossible to be actively engaged when you are one among too many others in a large lecture hall.
Hope this helps!
I second Professor Smith's reply. I haven't participated in philosophy chat rooms either, but I've commented on blogs by non-philosophers who post on philosophical topics. I've found the quality of thinking in those totally unregulated forums to be so bad it's scary. There are people in the blogosphere who are allowed to drive and vote who couldn't reason their way out of a wet paper bag. Philosophy is a discipline, one that takes hard work to acquire. Would you want to discuss medieval history, or quantum mechanics, or set theory in a dialogue format with just anyone out there? I wouldn't. Philosophy is like those other disciplines except that its problems are harder and more fundamental to our intellectual lives. Why do so many people think that being competent at it takes no training at all?
Just an addition to Nicholas Smith's suggestion that in order to avoid adhering to a specific philosophical viewpoint, one adopt a standpoint of 'epistemic humility', which I don't think is that easily achieved. (I, for what it's worth, don't think that one can up and decide to epistemically humble.) Historical, contextual, study of the history of philosophy can help to lead one to take such a position. As one sees the extent to which philosophical questions and answers are deeply bound up with contingent historical circumstances, circumstances which vary greatly from our own, we can come to see not only that philosophical positions developed by 'the mighty dead' were deeply contingent, but also that our own cherished positions themselves are deeply contingent, and may well be bound up with contingent historical circumstances. Reflection on the extent to which philosophy is contextual in this way may well lead one to begin to question the assumptions that we take for granted and that underwrite the philosophical common sense of our day (assuming that it even makes sense to speak of such a thing), and can thereby lead to new ways of conceiving of philosophical problems. And that, to my mind, constitutes at least one form of philosophical progress!!
I might add a modest point that could be helpful: It may not be helpful to see philosophy on the one side and religion on the other side of a great divide in terms of "final answers" and the offering of clear answers. Many philosophers today and in the past have adopted religious convictions, and many religious traditions (east and west) have either shaped or been shaped by philosohical inquiry. Within each of the great world religions there are multiple philosophically significant traditions that are experimental and speculative (non-dogmatic). So, for example, in Christianity there are materialists (Christian materialism is a new movement with philosophers like Peter van Inwagen and Lynne Baker) and dualists, nominalists and realists, utilitarians and virtue theorists, those who accept the static or dynamic theory of time (the so-called A series and B series), those who are libertarians versus compatabilists, and so on. And there is a similar diversity of views among philosophers in Jewish, Muslim, Hindu, and Buddhist traditions. My point is that even if one decides upon "the final answer" of a given religion, this does not at all bring the philosophical enterprise to an end. There is, rather, a vibrant great philosophical conversation over the centuries that you would be joining in which there is profound (and fruitful) diversity.
I expect that there will be some overlap in these skills, but strictly speaking, I think the special skill of a theologian will be the ability to organize reasons in such a way as to support certain religious views, the special skill of a politician will be to govern others in a way that engenders support from the governed, the special skill of a logician would be for finding ways to make inferences within a rule-governed system, whereas the special skill of a philosopher will be thinking "outside the box" in such a way as to allow progress on topics in which people "inside the box" find progress difficult or impossible. Philosophers are required not to allow certain religious views, or the need for popular support, to restrict their reasoning. Philosophers also often engage in reasoning where the rules of eviddence are not neearly as clear as they are in formal logic. But as I said, there will be some overlap in all of these skills. Many great philosophers have also been theologians, politicians, or logicians.
Many people do find philosophy quite difficult, but most people find that doing philosophy at least at some level is profoundly natural and fundamentally human. Aristotle said "philosophy begins in wonder." I think that's right. So my advice to you would be to allow your "wonder" not to be stunted by the artificial limitations of worries about grades. If you do start doing badly, have a chat with the teacher to see what you can do to improve. But here is something you probably already know: You do better at things when you find a way to enjoy them. This can be hard, yes; but it can also be great fun and very interesting...actually wonderful. So try to enjoy it, rather than fretting about grades!
The latter sort of question certainly is philosophical, but there is also such a thing as applied philosophy, and in particular, normative theory, which do attempt to provide grounds for specific kinds of decision-making. I do think that normative theories could at least provide reasonable grounds for making one decision or another about one's marriage, depending upon the circumstances of that marriage. For example, it seems to me that (other things equal) most normative theories would counsel abandoning an abusive marriage, especially where reasonable efforts to end the abuse (via counselling, say) have failed or have been rejected.
Professional publications in philosophy are always embedded within a context of contemporary controversy in some subfield of philosophy. Except in experimental philosophy, philosophers don't do research by conducting experiments, but we do still have to do research--keeping up with the controversies in our fields, and when we think we have something to add to those controversies, writing our books or articles in such a way as to make clear just how our own view differs from those others have argued.
A philosopher simply won't be in a position to publish an article until he or she has already been adequately trained in the broad basics of that area, and then also mastered the contemporary scholarly literature in the specific area of some controversy. One does not just sit down one day, without all this training and mastery of the literature, and decide to write a journal article just because one thinks one has a lovely new idea. Superb undergraduates have sometimes published professionally, and graduate students often also make such contributions. But mostly, those who make these contributions are those who have completed graduate training and kept up-to-date in their subfield's existing literature and controversies.