DX10 is the next-generation graphics engine. No, your 7900 won't do DX10. It means that while you will still be able to play games for the foreseeable - they will be backwards compatible with DX9 for a while to come - games will look much better with a DX10 card. Prices for those will come down. Nvidia's 8800 series will come down when ATI gets its cards out, which I believe is soon.