Looks like the AMD/ATI R600 may be delayed until Q2 - so if you are waiting for one, you will have to wait until around July :... however Nvidia appears to finally have WHQL'd drivers for the 8800 series of GPU's - but without DX10 support.
In the "Save our Wallets" department, there is a rumour that both AMD and Nvidia are set to release sub-$100 DX10 capable cards. Mind you, given that Nvidia still does not have WHQL'd DX10 drivers for its flagship 8800 products, and that AMD's R610 is still just a gleam in AMD's eyes (and ofcourse no WHQL'd driver for it yet) this is just speculation at this point - however intelligent speculation, as once DX10 is mainstream, there will have to be cheap cards for it. AMD at least apparently expects to have WHQL'd drivers for the 6xx series in time for CeBIT (March 14th)
Nvidia seems intent on capturing developer mindshare; they have released a beta version of a compiler that makes use of their math libraries for off-loading certain vector math to the GPU's for processing; leading to higher overall floating point performance. You can read more about it at their CUDA page. Personally, I prefer AMD's "Close To Metal" approach - documenting and allowing access to the actual underlying achitecture and assembly language for the GPU's - that way developers can "roll their own" methods of access, and probably use the GPU's in ways AMD did not think of.