AFAIK that is still plenty of card for WoW. I run a 8800GT(main) and 9800GT(4 slaves) and have no real issues. Graphics are medium settings.

Otherwise, the 9800GX2 (HD4870 is similar), GTX260 or GTX280 are upgrades to the 8800GTX (in that order).

The HD4850 and 9800GTX would be small upgrades.

I still don't know if WoW benefits from SLI/CF. Hopefully someone else knows.

Info based on Tom's Hardware charts.

http://www.tomshardware.com/charts/g...hmarks,30.html

So, personally I wouldn't bother unless it died or something. If you're simply looking to improve performance I would probably dump the $600 into a new MoBo, CPU and RAM (e.g., Q6600 quad core with 8Gigs and Vista 64).