If I weren't so devoted to Windows Mobile, I'd go out and get a BlackBerry Storm. If I weren't stuck on Verizon Wireless, I'd get an Apple iPhone. Currently, I use an XV6800.
Since the reality is that I'm on Verizon Wireless, I have a family plan, and almost all my friends use Verizon Wireless. So, I won't be playing with an iPhone anytime soon. (of course, I do have an iPod touch that has Wi-Fi, so I can still have fun).
Also, I am dependent on Windows Mobile for certain applications. However, this is slowly starting to change. I won't be surprised if I'm carrying around a BlackBerry in a few years. Especially since Epocrates now runs on the BlackBerry STORM, I may make that switch someday. I'm waiting for the BlackBerry that has a touch screen and a hardware keyboard.