To me their isn't such a great difference between DX9-DX10 gaming from what I have seen with a Geforce 8600GT For Instance Between F.e.a.r. Perseus Mandate vs. Bioshock. TruForm Rendering From ATi added a releastic effect and to Me graphics have looked that sharp for charecters. Ati had a Gpu with DX8.1 Graphics with some DX9.0 extensions. Here is an Example how much more graphic capability each version of DX9.0-DX11.0 Has. http://en.wikipedia.org/wiki/Direct_x_10#DirectX_10
I;'m Waiting For DX11 Max Payne 3-Doom IV-F.e.a.r. 3
Also haven't Caught up with F.e.a.r. 2 Project orgin DX10 to see how it compares with F.e.a.r. Perseus Mandate DX9.0C which looked really cool and realistic!