What?!?! They have a 9250?? :lol: Anyways, +1 to hunter. Also, 8600 is NOT a very good gaming card also. Look in to the ATI 4350/9600GT or higher for gaming cards.
The 8600 is much faster than the good old 9250. Of course you would be much better off with a cheap modern card like a 9500GT or a Radeon 4650 if you are only gonna do light gaming. If you want to play modern games (shooters and most RPGs) with at least medium settings then you will need a better card than that though.
also unless you got a Asrock with both AGP and PCIe get the card that will work with your current Mobo....But IMO both cards lack in performance , get a 4830 or 4770 if your mobo has PCIe if you still got AGP i recommend looking at a PC overhaul XD