I haven't read this thread, but
NO NO NO NO NO NO NO NO
First of all, the phone can handle 3.5G, but the network is still a 3G network for now.
Secondly, the AT&T network won't be unpgraded to 3.5G until late 2011, early 2012, so you'll be waiting all that time just to use the full potential of this phone.
Thirdly, by that time, there will be 4G networks out there...
DON'T BUY THE HYPE!!!