AP courses are phenomenal. It's not that they're particularly useful, or teach you a lot (in fact, compared to college courses they're a joke); its the time (and money) they save. The only useful AP courses I had were the ones where I learned to write well (Eng Composition, and Eng Literature), and that was because my teacher was good.
For example, I had 8 AP courses in high school. This allowed me to exempt 35 credits of courses in college, especially since I had mostly 5's (some 4's). More specifically, I'm a Chem/Biochem major, and I managed to eliminate all of my liberal arts classes (with the exception of language and "culture"), thus making my schedule entirely science and math now
If you're planning to do law, focus on science AP's in highschool, this may enable you to exempt these for your undergraduate studies. As a note though, most schools wont accept it unless you have 4's and 5's, so try to get these; 3's typically don't fly, unless you plan on going to a community college.
EDIT: Oh, and if you do become a lawyer, for the love of god, please don't be a greedy SOB who pushes for class-action suits for personal monetary gain