At one point I too thought about either law school or graduate school. I took the LSAT, did okay (above average but not uber-cool totally awesome) but after talking with my step-brother who graduated from a first tier law school I realized that as much as I liked that sort of logic in practice I didn't think I would like to do it for a career.
Personally I decided on applying to graduate school because I felt that is much closer to what I really want to do, so I took the general GRE about 9 months ago and I am scheduled to take the biology subject one this Saturday (yuck). So I'll see how that goes.
So, if you are anything at all like me I think you really need to talk to people who are in those professions (as in real life, not on the forums) and figure out what you really want. For me that was the hard part: finding out what I really wanted as opposed to what I thought I wanted.