As I still have about four years left until graduation (*), you should take my picks with a pinch of salt, but I consider myself a laid-back type of guy who'd rather be talking things over with my colleagues over a cup of coffee than being in the line of fire all day. I would also rather be in a setting where making a mistake or forgetting a technical detail meant an extra five or ten minutes of work for me, as opposed to being where it meant pain and suffering for someone else.
All in all, I'm first and foremost considering a career in pathology, radiology, psychiatry or occupational medicine, with infectious medicine (microbiology) being the dark horse.
But hey, that's just me...
(*) Medical education where I'm at (Sweden) is 7,5-8 years in all, and you can enter right after high school. It is also integrated, meaning that you normally see your first patients (living ones
) the second day of training.