well for now ,
3d gaming on PC is kinda not very good , most of the games dont have built in 3d but there are softwares like trideff 3d which convert them to 3d ,
there are very few games which support 3d but they then f up in the dept that support only Nvidia 3d vision kit , (crysis 2 is an example) but you can still make it work with trideff 3d
well as you know for 3d a vga card would have to process atleast 60 FPS per second or atleast 120fps per second in full fast mode and if we are talking about full hd then processing 1080p frames at 120 frames per second is a real hefty job so you ll need some kickass gpu for that
i have an SLI of HD 6850 , and things work smooth for me ,
we i cant really suggest a card for 3d gaming as all the upcoming games are getting heavier and heavier day by day , just settle for 2d gaming at 1080p , or spend hefty money on a really good card or an SLI
but i d suggest go for a motherboard with pciX 3.0 as all the new cards on PCIX 3.0...