If you go to a T6 law school, you're generally going to have the option of going into biglaw. Starting annual base salary for associates in major law firms is around $190K. Every year, your salary increases by ~$20K/year, and then you get a huge pay jump if you become a partner. Unfortunately, the hours at these law firms is brutal, and most people don't make it to partner; they either get canned or quit.
From a purely financial standpoint, law is probably the way to go. If you're extremely hardworking and bright, and if you can survive in a major law firm, your earnings will far exceed those of most physicians.
However, from a work-life balance perspective, medicine is usually better. As a physician, you have the flexibility to work fewer hours at the same rate. As a biglaw attorney, you either work extremely long hours or you quit.