Nvidia has one more beta drivers for Vista. As Nvidia is an only company who has DirectX 10 hardware out, it is the only one to compete. The new driver is still not WHQL but it gets you a few interesting features. It finally adds a beta SLI support for all Geforce 7 and 6 series of cards. It already made this work on latest driver version for Geforce series 8.
The new driver improves OpenGL performance and SLI performance at high resolutions and of course it fixes some of the compatibility issues.
For single GPU the driver supports in DirectX 9 for Geforce 6, 7 and 8 series while as you can expected DirectX 10 support works with 8800 GPUs only. OpenGL support works at Geforce 6, 7 and 8 series.
For SLI support in DirectX 9 mode works with Geforce 6, 7 or 8 series of GPUs and so does the OpenGL. Nvidia PureVideo HD works on all cards.
Please not that for SLI DirectX 10 support for Geforce 8800 GPUs in DirectX 10 is still missing in action and will be available in future driver. No need to rush as there are no any DirectX 10 applications, not even a benchmarks, not to mention games.