Tungsten E owner and so far so good.
As for my school programs I have Taber's, Epocrates, medcalc, and a few extra "freebies." I won't subscribe to Epocrates next year as it cost more for one year than a Davis drug guide or any of the other drug guides and those are yours for life.
The other program I would reccomend is RNnotes. I don't have this on my PDA as I purchased the little book before I knew it was available as a program. Either way this is a very handy tool. If you have a B&N or Borders bookstore near you, check out the paper copy but buy the PDA version.
Trial version software - I downloaded several "trial" versions. My advice, unless you want to see the color and layout of the program, they are otherwise useless. You don't get to "try" the entire program for x number of days, you get to try a few entries of the program. In most, you only see entries which begin with A and that is it.
I have lugged books to school and clinical before. What a load! This is by far easier on the back, easier in bad weather, and with most of the programs purchased from Skyscape, are linked to each other so if you are searching in one program and there is information in another that corresponds to the subject at hand you can link to it.
Good luck, whichever model you choose. There are some very knowedgeble folks on this board who actually sell PDAs who are a wealth of help and knowledge. (I don't happen to be one of those people