NVIDIA's first mainstream DirectX 10 compatible graphics cards will be released in spring 2007.
Once Vista is out and real and we guess that will be during January, there will be a huge gap between the DirectX 10 API and the hardware that supports it.
At that time Nvidia's G80 boards - Geforce 8800 GTX and GTS - are going to be the only two products to support Direct X 10. ATI's R600 is delayed until at least February, while G80 launches on the 7th of November just some three weeks from now.
Nvidia is keeping up with its deadlines and is working hard on its next G8x mainstream part. It schedules it for spring probably Cebit-ish time - March or so, 2007. We don’t know the specs but we believe that it won't be unified, either as it will derived from the G80 marchitecture.