Trying not to be a fanboy, I've stayed away from the iPhone (I've owned 3 ipods and 4 macs), but it just makes the most sense at the moment. If android ever becomes a reality it will make for a nice alternative though. But for the time being:
- Windows Mobile: I currently own a WM5 phone, my second WM device, and I can't stand it anymore. Constant crashing, losing my data, alarms on the fritz, memory leaks, etc... After 6 years with WM I'm completely fed up, you couldn't pay me to use another WM phone. The fact that they just add eye candy to the OS without fixing any of it's problems just aggravates me more.
- Blackberry: Love them, except for the need to pay extra for the blackberr