If you want, as you said in first post, the best card, I dont want to make some bragging here so I`d just recommend 2 cards which I have no experience in, but of which I have heard has Tremendous performance, The Ati Radeon X1950XT Pro, which is said to be working very good at XP gaming, and the GeForce 8800 GTX 768 MB XXX from XfX which, will work for Vista (Direct X10 support.) and as far as I know, SH4 will support Vista eventually
Ur friend in the pacific
S!
Red Hammer