As a former sufferer of said dilema, I am obligated to share my solution: The best AGP video card to buy right now is a PCI-Express video card.
Flame away, I've got my reasons (I know its OT, but hold the judgement for a sec).
We all know that pci-ex versions of the same card sell cheaper because they make more, law of economics, yadda yadda.
And rather than buying a fancy video card for your old computer until part of it finally dies (like say, the motherboard itself).
My solution to said problem was simple: pawn off the AGP boards now, and find a pci-express solution for your chip/ram/etc.
You may claim these solutions do not exist, but I've managed to stuff an old s478 P4E and s754 A64 into pci-ex boards (P4RD1-MX, Infinity NF4X). Same chip, same ddr1 ram, same drives, same/better overclocking, just 2 bits get tossed in the lake (board, vid card...)
Granted the OP didn't mention what chip he had, but if you like gaming, then you want a slick video card, and well, why buy a slick video card for a dying computer/dead socket(???). I say, find a new board, and get a heavy duty video card that can be moved to your new core2duo rig next year (or am3 if it proves itself beyond word processing).
As for saying I smoke crack and post OT, umm, yeah, any x8xx card gets my vote, x1600 gets thumbs down, and the 7600gs is 'meh', sm3 without the power to use it sounds like 64bit windows hype to me