I prefer the Palm OS over Windows. It takes up less space and is more intuitive. I don't use Windows on a PC either, it is clunky and bulky.
I use a Tungsten C with a built in keyboard, like a Blackberry. They don't make this model anymore, but if you can find one used I recommend it. It has a nice big color display and the battery lasts for about 2 weeks without needing a charge. It has built-in Wi-Fi, too.
Lexi-complete has got me through most everything. I use several of the applications. Lexi-Calc is good for calculated ideal body weight, creatinine clearance, heparin drips, etc. Lexi-Interact can check drug interactions, Lexi-Analyze will check IV compatibility. It's just a good suite to have on hand. Every hospital seemed to have different references, so it's good to have something that you are used to, so you can find information quickly.