IMO get the Nforce 630i chipset mobo. it has building in ~7300 with HDMI video out. perfect HTPC mobo if you ask me. I have been running one for a while now with no issues at all. HDMI out to my 50" HD. Also has great audio on board if you chose not to use the HDMI (I don't use the hdmi sound).
for agp cards this probaly good as it gets. for the money and what you wanna use it for.
if you were building a new cheap HTPC i would grab a 780G AMD board and throw in a cheap x2 total cost for both items be around 100 bucks total.. course you would probaly need new ram aswell judging by your agp current mobo.