The whole Direct X 9 vs Direct X 10 debate can be summerized as the following.
Direct X 9.0c means compatibility with 95/98/ME/2000/XP/Vista
Direct X 10 means, go buy Vista.
So stick with 9.0c for as along as you can, it means you will reach alot more users than you would if you used 10.
Also you will find that any Direct X 9.0c graphics card and game and reproduce the screenshots shown on the first post if for no other reason than that no graphics card with DX10 archetecture exists yet so logic dictated that those screenshots were produced with a Direct X 9 based graphic card. Until nVidia, or ATI or someone else releases a DX10 based card, I'd take such screenshots with a pinch of salt, at best you are alooking at emulated hardware that's almost certainly being rendered like a 3D app, rather than in real time.
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