GMA 3100 Woes and Card Recommendations

Hey. I've got a motherboard with the Intel G33 chipset and onboard GMA 3100. Mind you that's very different from an X3100. Anyway, with a GeForce 8800 GT the system installed and booted just fine. But when I take out the 8800 and hook the monitor up to the onboard VGA the system won't boot. It hands before the spinning gear can even appear. I installed using iATKOS v7 and I installed all the video drivers it had. I've seen elsewhere on the net (after googling) that people have been able to get their systems to boot but just run at a fixed resolution or without hardware support. Does anyone have any suggestions for what I can do to make the system at least boot up? I've got the chameleon 2 bootloader, but I'm not sure how to specify boot options for Darwin. I'm completely knew to this prospect of running Mac OS X on a PC, though I do have several Macs.

I do plan on getting myself a decent nVidia card in the near future. I'm looking at either a GeForce 9800 GTX+, a GTX260, or maybe even a GTX280. Anyone have any recommendations for which will be the most compatible?