Kind of early in the thread to be chiming in since I probably represent an outlier in terms of my experience. I'll be interested in seeing what some of the other folks have to say (tyrion, Voltron, UncleErik, etc).
In my case, I never intended to practice law nor have I ever accepted for one moment that my seat in my law school class was wasted space. It's not like I didn't care or didn't study. It's not like I couldn't have, at some point after graduation, decided to go back and take the bar, get a job, and become a good lawyer boy. But people sure did give me enough grief about preventing someone else from realizing their dreams. I thought that was a bit whacked, in that I had my own dreams, so who is to judge?
My interest was in teaching, and when I started law school I was on temporary leave from a Ph.D. program in accounting. My thoughts at the time were to eventually go back to finish my Ph.D. (after law school) and to teach at a major US university (accounting, taxation, and business law). In any case, I was fortunate enough to have wisely chosen a law school that was sufficiently non-T14 (or anything that would resemble T14), such that I was able to teach accounting at that same university on a full time basis while attending law school full time, and still managed to finish in the top 10% of my class.
The main reason I did so well in law school was that I really didn't care too much about my grades, but I studied like crazy simply because I tuely loved the learning process and found most law courses to be fascinating, even things like admiralty law, intellectual property, or trusts and estates. I'm quite sure that I'll never experience anything like it again in terms of the intensity of the experience (given my other commitments at the time, teaching full time and being a textbook author which also took a lot of time).
So to me, that was the buzz. Just reading, thinking, discussing, and enjoying the learning process without really being concerned about where it would all lead or what the payoff might be in the end. In a sense, this is exactly how law school was intended to be approached from the very beginning. It's only in recent times (probably the past 50-60 years) that the study of law or the practice of law has become more about the "business" of studying law or the "business" of practicing law. In any case, it's a luxury that I don't think enough people allow themselves while in law school. But of course the same is true of any other discipline you can think of. How many people do you find at the main university library on a weekend just wandering the shelves and looking for something interesting to read? Something that is not "required" reading for their courses?
Anyway, that's all I know, I suppose. I've never practiced law (as such), so I couldn't tell you the first thing about that. But I do know that my legal background has been put to good use many times in my life. Mostly when I was in private banking, but also with resepct to many things I'm involved in now with a number of companies that I serve as a director for. In my view, it's something that you'll never regret, especially if you pursue your studies with the right perspective.
There is so much to learn from the "process" of studying law, it's just unreal. To me, it was a strong enabling experience in the sense that once it was all done (graduation day), I felt that I could do anything that I set my mind to. Whether you'll ever remember anything or be able to put it to practical use is quite another matter, but don't be completely discouraged by all of the practical considerations (job market outlook and so on). Weigh those factors in your decision making, but think about what you really want to be happening in your life as well.
Make no mistake about it, however, in that my presepctive on the whole thing is quite different than that of most people. I'm an outlier in terms of my experience because what mattered to me was the learning process itself (that's what I was there for) and thus I never allowed myself to become jaded in any way by wondering whether it would all pay off or whatever. Most people eased off in their studies considerably after the first year grades were out, but I studied just as much in all 3 years because I actually enjoyed it, believe it or not! In fact, I went back to a different (but equally non descript) law school 5 years later to get an LLM in taxation and enjoyed it every bit as much.
To me, that's where it's at in life. Enjoy what you're doing as you're doing it. Give it your best at all times, then you won't have any regrets. The rest will all work itself out one way or another. You're not responsible for solving the world's economic problems, so why bring all that upon yourself? If you're good enough at what you do and work hard enough, you'll have plenty of opportunities when you graduate. If not, then go to Plan B and work equally hard on that. If not, then Plan C. Eventually, the rewards will come.
