Hey there,
Please post your current specs! As for whoever said "Stick with AGP", there are a few disclaimers I have - AGP is on the way out, as PCI-E is taking over with 16X Bus Speed - AGP is still top of the line and cards that run that bus (All of them except 7800 GTX as of yet) perform well. If you plan to go SLI in the future, or anything crazy, consider having a PCI-E graphics card and compatible motherboard.
-Sean