The only advice I can give you is to avoid the 9 series nvidia cards; from what I'm told, their performance boost is negligible vs an 8800, and not worth the price; people're basically disappointed in them, and an 8800 should be MORE than enough to last you awhile, especially if you end up going SLI with 'em like your sig says lol

I'd say a minimum of 10fps to be "playable" though, 20-30 for smoother looks ;p I average 20+ fps on my trio in cities atm, unless the crowd is the usual sunday night "LOL GATHER AND IDLE IN IF ALL NIGHT EVEN THOUGH IT LAGS TO HELL" I drop to 5-10 with lots of load lag coming in lol