At 1680 x 1050 you need at least 4xaa imho.
Yeah, if you're using a 22'' monitor. On my 20'' - I have a .258m dot pitch - and the difference between 2x and 4xAA is negligible. So I only run 2x on most of my games.
It honestly not the lack of AA that bothers me about the card - it's the massive power consumption. That and the fact that G92 and RV670 which are hopefully a little over one month away will be much more attractive.