First off rather than the phone its self lets talk service provider first. Sprint and verison would be fastest id imagine being that they are EVDO data connection. Next up would be EDGE data providers like Cingular and T-Mobile. As for the rest, who the hell knows. Price for a data plan is a major concern in second place. Coverage area would be my third concern, then last would be the actual phone. I have been with AT&T which then was bought out by Cingular, so i went from basic GPRS service to EDGE data network. I pay 25 a month US for unlimited EDGE data and for what i do mobily with the 770 web, chat and so on it works fine. I have also spent many an hour trying to figure out optimal setting to rape the most from CIngular that i can. I currantly have a SE W600i and a quick speed test (best out of 3 sites) just now shows.
http://performance.toast.net shuttle+text=243 kilobits
http://www.dslreports.com/mspeed 200k test= 203 kilobits
http://bandwidthplace.com/speedtest/ select other then EDGE network=589.9 kilobits?

Mind you its midnight and the network is about 30% slower at peeak hours.