If your sig is correct, then you have an abit IC7 which is a nice board. I don't think you'll see much advantage to going with pci-express unless you want a top of the line $500-600 card that isn't available in agp.
yeh ive been lookin at that one but now that the 7900 series came out i think im gonna try to go for one of those, but dont want to pay another 300$ for a cpu and 150 for a mobo..so im tryin to just find a 478 pcie mobo