ricanflow, not to undermine you, but agp does suck. You said it yourself, older standard. When something is older than something else, generally it sucks in comparison to the newer equivalent (assuming the newer standard is not glitchy as all ****).
AGP's options are very limited compared to PCI-E x16, so in the long run you'd be better off upgrading your mobo. If you need proof, here:
AGP 2X/4X(6), 4X/8X(120), and Pro 4X/8X(1) = 127
PCI (48)
PCI-E x1 (2)
PCI-E x16 (404)
I'm pretty sure PCI-E x16 wins that one.