PowerColor
OC editions of the 5850 PCS+ ... Powercolor is actually going beyond the reference design specs and offers higher clock speeds of 760 / 1050 vs. 725 / 1000 on the normal cards. While not making a huge difference it should still give a little extra performance boost to the card.
OC editions of the 5830 ... (825c/1050m).
And the card that always catches my attention .. the Liquid cooled 5970 ... yummie :)