After having played with a WP7 device for about 8 months, I now have to say it's not for me. There are two reasons.
Firstly my current phone was lent to me, and now has to be returned. But this is not the show stopper. I'd buy a new one tomorrow if it wasn't for the second reason. The main reason I'm giving up on the Windows Phone 7 is that I cannot find a way (that works for me) to back up my telephony data. My text (SMS) messages and calling data are important to me and in order to continue using these devices I need to have a way to record and back up this information.
Because Microsoft has made it incredibly difficult to back up this data via their API's I cannot buy or even write an app that will let me back up this data easily or in fact at all. So finally I gave up trying.
It's a sad day because for all of it's flaws, the Windows Phone 7 is one of the most ergonomic phones I've ever used. It was mostly intuitive and in the main just works. And looking at the future of Windows Phone and Windows 8 - the metro paradigm (the one on the Phone) look like it's the future of Windows.
I'm now looking at either an iPhone (deep sucky in breath) or and Android Phone (slightly less sucky in breath).