I am going to repeat and elaborate on my thoughts.
I would really strongly caution anyone considering going to law school to not only look into the profession very thoroughly and also do some soul searching about why you are getting into the field. If you find yourself coming to some kind of conclusion about higher income or having a "safe" career, I would strongly recommend you rethink your choices.
Spending the last year or so of my life in the "document review" world, I can tell you it is no longer the land of misfit toys. There are a lot of good lawyers who in a better economy 10 years ago, would be safely earning a good salary someplace (for the record I am not talking about myself). The reality of the situation right now is that finding an entry level legal job is very difficult. If you miss the boat for some reason and fail to go the traditional paths of a respectable clerkship or a summer associate position, then you are going to be rolling the dice.
I'm friends with a lot of lawyers and they work across the spectrum. My law school roommate was class valedictorian, law review, etc. and works in "BigLaw". Some might say he has the dream job, but I sometimes wonder if law school applicants, 1Ls, etc. truly comprehend what working at one of these firms entails. As others have alluded to, there is certainly a good chance my roommate could be making more working in finance, at least at the moment, than in law. Also the suggestion that once you make it to BigLaw you have crossed the finishline, is not accurate. Especially in this market, you need to make it to BigLaw and then prove yourself, or you are out in 2 years. There is a steady stream of talent and not a lot of jobs.
I also have a number of friends who are at the smaller firms. 4-5 lawyers doing some insurance defense and a variety of other specialties. Honestly, I think that 10-15 years ago I would probably have found myself at a firm like one of these. The problem is that small business and real estate are hurting right now. A lot of these small firms were pulling in respectable amounts of money a couple years ago, but right now times are tough. One friend was told by the partner at his firm that he was making 500k a year a few years ago and this year he had about 75. It's a common story. It doesn't mean every firm is going bankrupt, but I think in general lawyers at these firms are working a lot of hours for way less money. It can still be a decent life, but again you have to ask yourself if three years of school and potentially 100k in debt are really worth it for just decent.
Finally, I think that in general the field is in a state of flux right now, which is the biggest reason I would caution people considering getting into it. I think even a large number of older and established attorneys are shielded from these changes somewhat for the moment, so they may give potential students a false picture of the profession (albeit, unintentionally). I think a lot of changes have occured in the last couple years and more changes are coming. A lot of lawyers have somewhat of a false sense of hope that things will be going back to the way they were once the economy improves (if it improves) and I am not so sure that it will. The combination of a bad economy and a dramatic improvement in technology are cause many law firms to become "leaner and meaner" with less associates doing the heavy lifting/grunt work they once occupied their early careers with. I see the beginnings of an expansion of reliance upon technology and a changing of roles within the law firm structure and the industry as a whole.