new system came with 6600gt, upgrade or hold out

just bought a system from a nice gentleman on anandtech boards

venice 3000+ running at 2.2ghz
2x512 patriot cas 2 memory, red heatspreaders
pci-e 6600gt personal cenima card
80 gig
2x 250 gig
nice case
modular 500 watt ps

a few days prior had purchased a 6800gt agp from newegg as well as a corsair value dual channel 1 gig ddr kit and dvd burner to upgrade my computer as well as my wifes, now going to return the newegg stuff. should I then buy another pci-e video card from newegg? or hold out for another day. would love sudgestions on a card, don't want to go over 150 to 200 if I do decide to upgrade the 6600gt, currently playing WoW, and plan to play age of empires 3, and the current fps and rts games soon