i had a biostar tforce 6100 for amd64 and i loved it, i could not believe how stable it was. it blew ny epox, 2 asus sli boards, and dfi out of the water as far as stability is concerned. i would go a month and a half between reboots (idle timer in irc).
when you say you want onboard video what do you want to do with it?. the nvidia 6100/6150 onboard kinda sucks, it gets roughly half the frame rates you would see with a $60 9800pro. i couldnt even play bf1942 on high settings, med/low is all it would pull and that is with a 2.75 gig 3700+.
ati has an express200 chipset with a x300 onboard but it is a crippled x300, scores the same as nvidia's so if you even want to do moderate gaming with older games you should look elsewhere. look into a cheap add on card.