If you don't want to go the motherboard route, I would say 7500 PCI is your best bet.....I think they are around $70.
But with memory, CPUs, being so cheap, you may consider going that route.
You could prob get into a Nforce2 board with built in video ( agp slot for future expansion), 17000XP, 512 MB, for $225-250.
you could kick it up too a baron 2500, for about $80 more.
Just a thought
BTW, I hate to admit it, but I am using a TNT2 M64 right now.... I am a few days away to getting my son's old GF2 GTS-V.....lol