Even though I am a huge gigabyte fan I would have to say nay to that board because of the uli chipset,, That chipset had issues with bridged nvidia cards (that must **** nvidia off because they purchased uli) I was in the same boat as you. Iwanted a 939 amd and 8xagp.
I went with the asrock dual sata2 that has 8xagp and pci express 16x , then I found out about the issues with nvidia cards. I returned the board and wanted the k8ns ultra 939 (only nforce gigabyte with 8xagp and 1000fsb)(2000htt) but couldn't get one so I got This Asus A8V
and I love it. Here's a screenshot of my system with the uli chipset and then the A8V (The board thought my 6800gs was a pci (NOT PCIX) card not 8xagp. Can you see a difference?? lol
I know having both pcix 16 and 8xagp on one board is a tall order but once bitten twice shy.
Edit -- This is the Gigabyte to get if you can find it