Alot of lawyers don't make 100K. In fact, in alot of newly minted lawyers in NYC don't make 75K. It depends on one of two things: which school you go to (and how well you do), and/or how hard you work once you get out.
Don't go by "average" income figures, because the high end of the spectrum is MUCH higher than the low end. Starting salaries range from 35K - 200K. Most are closer to 60-75K.
The best advice I can give someone thinking of law school: Study your *** off for the LSAT. Do practice exams until your brain bleeds. Take primer classes. Then do some more practice exams. Then apply only to the big schools. You're going to pay through the teeth for law school even if you go to a crappy school, and having gone to a reputable school is worth the extra expense. It will make it that much easier to get the big $$$ employers to look at your resume. If you don't score well on the LSAT, you'll just have to work that much harder to find a job when you graduate.
How much you earn as a lawyer is directly related to how much business you can generate. If you sit on your behind doing projects for other lawyers/partners, you can only make good $ in a bigger firm (in which case you need good credientials). If you can drum up your own business, you can make good $ working from home in your PJs. Either way, expect to work your *** off.
If I could do it over, I'd also go for an engineering degree. I might do that anyways, if I can convince my wife to pay the rent for 4-5 years.
BTW, I don't think education is always proportionate to salary. It is in most cases, but not always. When I graduated from college, I looked into getting a PhD in Literature, until I found out my profs made less than I did as a bartender. That's why I went to law school.
