Eh.. maybe this is just me, but I don't call somebody who studies philosophy a philosopher. I call a person who has produced some compelling work of philosophy a philosopher. I'm a philosophy major too, but I certainly wouldnt call myself a philosopher, and Im guessing you arent one either.
As for the usefulness of the study of philosophy for medicine, I love it. It helps a lot when critically examining research so you can draw your own conclusions rather than simply accepting the conclusions of researchers, or taking everything you read in a science textbook as the truth, a bad habit a lot of science students have. That kind of insight is what leads to innovation in science. A background in philosophy is also very helpful when questions of bioethics come up, and thats inevitable for doctors.
I'm a little confused by your portrayal of philosophy, though. Sure, a critical spirit is good, but I find that making the most charitable interpretations possible even more enriching (i.e. what interpretation makes what this philosopher is saying make the most sense?). Otherwise you'll probably overlook some brilliant work--Hegel's a great example for this--because you didn't look deeply enough into it. Usually the way things appear at first glance turns out to be wrong, and if you dismiss things too quickly you won't learn much. I asked my first philosophy professor what I should do to succeed in philosophy, and he told me to try to defend the philosopher, because thats a bigger challenge than critiquing. It's the best advice I could have been given.
Furthermore, you probably should study the philosophy of science more. I recommend you read Kuhn especially. If you're interested in science, you must understand that science requires accepting (at least at the time you conduct an experiment) certain things as truth. If, say, you do an experiment and get results that contradict Newton's laws, you're probably going to think something is wrong with your experimental setup rather than Newton's laws. No, nobody would question Newton--and for good reason, not only because Newton's laws have been well tested, but also because if you don't start with some kind of framework accepting certain hypotheses, you can't make any progress.
As for ignoring common sense, I don't think this is a fair characterization of philosophy. Aristotle for one paid a lot of attention to common sense to see what knowledge he could derive from it. Of course not everyone agreed with his philosophy, but thats just the point.
This disturbs me the most:
I think "money doesn't matter" is one of these conventional folk-wisdoms that philosophy taught me to proudly ignore and think for myself. The same goes for existence of god, existance of soul or a just world.
Philosophy doesnt teach one to "think for oneself," but to use reason (unless you're in the anti-rationalist camp, in which case... well, let's not get into that). On the contrary, as I read it, thinking for oneself is very unreasonable ("I believe this way because I want to, and I don't care what your argument is.") Let the logic persuade you, not your own inclinations.