I agree, unless you can't afford it right now (and you may not be able to), it's probably time to upgrade from the 9800 Pro anyway. You can get something pretty decent like a 7800GT for around $300, or maybe a 6800GS for closer to $200. If you can't or don't want to spend the money for a new video card right now (understandably so, since the price for a "good" video card just seems to be climbing with each passing year), then the ASRock AGP/PCI-E board is a good choice. You could also get a nForce3 motherboard with AGP, but I think I'd still go for the ASRock since it has an upgrade path for PCI-E cards in the future whenever you're ready. I have a (very) long thread about this board in the motherboards forum,
here, you might want to skim over it to look at other people's experiences. Mine has been very good (using an Opteron 170 and AGP 6800GT right now), but a few have run into some driver/other issues.