The AT&T GSM rollout is only partially compleet, so if you're thinking of going for it you need to do more research on what the coverage is like in your area, and the areas that you might visit. All in all, unless you want the $100/unlimited plan, there isn't much reason to swtich.

If you want to stick with your 8260, you can always find extreemly cheap non brand name batteries which aren't nearly as good as the nokia ones. Reall though, if you've had your phone for two years, it's time to go in to a company store and tell them you're willing to renew for a year for a good deal on a phone. You can probably pick up an 8265 for the same cost as a decent battery.

Matthew