Well here are the reviews of it.
It seems the X1900XTX beats the 7900GTX on higher resolutions and AA by over 1000 marks, and it beats the 7900GTX in COD2 on higher resolutions. On default res and things the 7900GTX beats the X1900XTX by 192 points. But I think I'll take the X1900XT/X because it can handle AA and higer resolutions better and shader-heavy games like FEAR will beat it out. The 7600GT beats out the 6800GS in COD as well.
Edit: here is a more detailed review of it.
It seems the 7900GTX beats the X1900XT/X on lower resolutions with no AA but the X1900XT/X shows it's strength with AA and higher resolutions. I like to play with AA so agian I'm going with the X1900XT. Even with no AA the X1900XTX beat out the 7900GTX slightly in Battlefield 2. These cards are VERY evenly matched.
Interesting if you look at HD gaming Loast Coast the 7900GTX is noticiably better, but I'm not going to be playing at those resolutions so this is not that big of a deal to me. But if you look at HD HL2 Canals you will see that a single 7800GTX 512MB beat out the 7900GTX, so nvidia's drivers aren't perfect.
Both of these cards are real screamers and either way you're getting a great card. Although I beleive the X1900 is the better one to go for it's shader eating power.