After my 6-month hiatus with HTC Desire (great phone, btw), I ended up going back to Blackberry. The lack of a physical keyboard was just unbearable (to be a little dramatic). Also, my work email didn't sync with my Desire and messaging wasn't as fluid as a Blackberry.
I had a 8100, 8520, and a 9700. So I felt like I had a decent grip on the BB OS. After picking up the 9780 this time, OS 6 gave me a nice blend of familiarity and refinement.