The videocard battles

AMD/ATI is set to release their new video cards very soon to open up competition with NVIDIA. Despite this it behooves one to wonder how you should properly judge the performance. There are presently no Direct X 10 version games available for MS Vista. Futuremark is preparing a benchmarking software for Direct X 10 which is not yet available. I assume you could make benchmarks using available games but this would benchmark games written primarily in the old platform of MS Windows XP. For users of Windows XP this would still be a good choice of benchmarking but what about MS Vista users? How will they be able to know which video card (NVIDIA 8XXX series or AMD/ATI) will bring best performance to Direct X 10 and MS Vista? I suppose we'll have to wait until games like Crysis are released to make such a judgement.