All three of the phones you listed are probably supported, but my most coveted phone feature is the ability to sync with my iMac using iSync via Bluetooth.

I wouldn’t recommend a Blackberry unless you were going to use their email service. Other than that, I can’t say much cause I’ve never had one. :P

iPhone is nice, I will admit, especially if you don’t want to carry around other devices for multimedia. However, as you’re with Verizon, you’d have to switch over to a new contract with AT&T for it (though I suppose you would need to do so even if you were a current AT&T customer). Lowered price definitely is a plus though- it’s more in line with other ‘smartphones’ out there. Oh, and assuming you for some reason would want to go to town with its internet features, I hope you’re within a WiFi hotspot’s range, as EDGE seems to be verrrry slow in loading real (non-WAP) webpages. I’ve played some with it at a store, but don’t own one ($$ + some more $$ = x_x)

Windows Mobile is where I personally have the most experience, though that’s with the non-phone side of it. I even got an older Pocket PC phone with WM for the heck of it, but in general I’m doubting to how suited the OS is for phone usage. If you also want its multimedia capabilities and large app. base, then I would say try it out; otherwise, I think there is a fair learning curve involved. Note that there are really two versions of WM out there running on phones: Professional (uses touch-screen) and Standard (no touch-screen). The non-touch screen version is a lot more intuitive simply because you only have a keypad to use, just like other basic phones.

I guess there’s no love for Palm OS Treoes :P, though it’s getting pretty old now as well…refresh after refresh. I would have sprung for one of those, but for whatever reason they have never came out with one that has built-in WiFi (and they also doesn’t support WiFi SDIO cards should you want to add it on). Eh.