I think the 7850
would be the best for you considering your budget is over $200. The 7850 outperforms the 560 ti 448 and par with 6970 and 570 (according to tom's hardware). And done with only one 6-pin PCI-E connector. Except you really want to wait for Mainstream kepler (could be the GTX 650 or 660), this 7850 is a really nice GPU to consider.