A ASUS SKT-AM2+ CROSSHAIR II FORMULA S/V/L 5200MT/s
Or go for option C 4870X2 in a few weeks.
Thanks so much guys going for x2 4870 in few weeks.
I'm not sure what the price/performance for the 4870 x2 will be. I'd go for the 4870 myself. I hate the dual-GPU cards and try to avoid them if at all possible.
Besides, if you just settle with a 4870 which you can get for $280 or so depending on where you buy, you can wait until the fall for nVidia's cards which will be a much better high end choice than any dual-gpu card.