hey, that's kind of a sore subject. My school insisted on giving me a BA in BIOLOGY.
This has been asked thousands of times. Here are my opinions:
Bio/Biochem includes the prereqs, good if you´re short on money for extra semesters. Decent jobs/ PhD opportunities if you don´t get in.
Hard sciences and engineering are good for getting jobs, good if you don´t want to put all your eggs in one basket.
Communications/Playground management/whatever else your football players are majoring in are good for your GPA: good for getting into medical school, real bad if you don´t get in.
More difficult liberal arts majors are probably the most fulfilling (unless you like sciences, in which case ignore this). Good if you want your college classes to be as memorable as your college outside of class, but this is both as bad as Engineering for getting into med school and is as bad as communications for getting a job if you don´t get into med school.
I went with engineering.