I agree with the above opinions in that you should wait, at least till the game comes out. Then figure on getting the best bang for your buck. Right now, the 9800 256 is going for low prices everywhere.
I loaded an X800 pro (XT supposedly isn't available til Oct 1st) just in time for a LAN last Saturday and it made absolutely NO difference compared to the 9800 pro I've been running since it came out. I was mightily dissapointed.
Of course, I also hope it's my system too. (P4 2.4, 1.5GB pc2700 Corsair RAM, SoyoDragon2 that only has 4x AGP)

. I'm thinking if I upgraded to a mobo with 8x AGP & at least a 3.2 P4 that may make the difference. If so, I'll let you all know. I just have to find a decent SFF one for my IceCube. <looking now...>
Personally, I will be waiting for the PCI-E before making a full upgrade. Especially if a mobo with 2 PCI-E x16 slots to use NVidias SLI card (if it works well). I still have very fond memories of the x24 (3dfx VooDooII SLI'd on one card). Even though it was $600, it lasted me over 2 years.
I guess we'll see what xmas brings this year...