I'm using an HP iPAQ rx3117. It's pretty nice, and I got a good deal on it (refurbished). I haven't been able to afford extra memory for it yet (want to get a 1 gig memory card), so I'm a little light on programs. But, as a student nurse, it's extremely useful.
I have Epocrates drug reference, Lextionary (a dictionary), I can type notes with the onscreen keyboard about as fast as I can write (and it's much more legible

), I can get on the internet with it (if there's a wireless access point available), and I even have a few games on it for those rare occassions when I have nothing more important to do. When I add more memory, I'll also be using it as an mp3 and movie player. But, with all the books and materials, parking for clinicals, replacement uniforms, yadda yadda, it'll be awhile before I can drop that extra $60 on memory.
But, to make a long post short, yes, it's definitely worth it.