[eatbuckshot]

I feel that if you'll be implementing GTD you would need a phone that's stable and incredibly responsive so that technical issues don't get in the way of your organization. IMO I've gone through the 6600, xv6700, xv6800, and touch pro 2, and the responsiveness of them is exactly inverse with the >5yr old 6600 being the fastest. I've been trying to look at GTD and really I feel the 6800 is too slow and lacking memory for constant use.

I recently got myself and LG fathom, which for the first time in 5 years i've actually been satisfied with the blazing performance.
So if you do like windows i suggest this phone. As for software, it's true it's difficult to find good software for winmo, but the forums help with that. (Try my life organized for GTD software, and Opera Mobile 10 is among the best browsers for winmo(great fluidity and tab support even some flash), there's also a free wifi wireless tethering application that we all use)

If you have verizon and are eligible for an upgrade you may be able to get the LG Fathom for $0.01 from amazon wireless.

Though this phone is new, so there hasn't been any custom developments for it. However, out of the box, it's the most usable windows mobile phone i've ever had including heavily modded ones. I just figured out how to get real GPS working on it too with google maps.