I am read a lot of rumour saying radeon R800 aka radeon 5xxx series will release earlier than windows 7 release ( windows 7 release on October 22, 2009 )
Here some list List of released and unreleased games with DirectX 11 support
BattleForge
Crysis 2
Battlefield: Bad Company 2
Dirt 2
Race Driver: Grid 2
F1 2010
Taken from wikipedia
Disclaimer. We can not guarantee that the information on this page is 100% correct
i’m predicting price of hd4xxx will drop after hd5xxx series release 
Ryan
Looking forward for it. Can't wait to buy 5870 X2.