do some research on this site for past posts...
As for me my Palm Tungsten C works great and has lots of power and memory.
As for software, most publishers of drug books also publish for Palm and you should get the same one you are using for school for consistancy purposes...
Ther are many who go to the free downloads like Epocrates etc for other software...
As for me a drug guide, a dictionary, a lab value have been all I have needed.
As I said, do some research everyone has an opinion on anything "technology" and then make your own decision with your budget in mind.
good luck, dave