ExtremeTech has posted the first in a three part series covering the people behind the new Direct3D 10 API. The interview with Microsoft's David Blythe and Chris Donahue reveals some of the processes and decisions behind the new API as well as giving some insight into future directions for the API. It's definitely worth reading.  Here's a taster:

ExtremeTech: It didn't take long for games to take advantage of DirectX 9, but it took a really long time before any games required it. Do you think that's going to happen more quickly with DirectX 10?

Donahue: It's difficult to say if only because the consoles, as you mentioned before, Xbox 360 and PS3, are fundamentally DX9 parts. We're kind of back into a situation we were in before, where there's a lowest common denominator across hardware. If someone is going to do a game that is multiplatform and they want it to run on the consoles, they're going to have to do a DX9-style pipeline anyway. So from that perspective, there are companies that do just one generic cross-platform component and try to hit everything, then there's the guys that do the really exploitive type stuff.

I think you'll see DX10-only in the next two years, certainly. That's about as close as I can pin it, because part of it is going to depend on adoption and installed base of DirectX 10 hardware.