heheh yes bigworm, when my x800GTO failed a year and a half ago and i was left with only a RAGE 128 PRO, it still ran HL2 at around 30fps (albeit with cruddy settings).
anyway ... if you have only PCI, then i'd recommend
x1300PCI. sure, it's overpriced, but it's the fastest and most feature-rich card that is PCI.
if you have PCI-E, the
x800GTO is still a steal at 86 bucks, and the
x850XT is great at 120 (4 more pipes than 7600 and faster memory, but lacks support for SM3.0... it's not too much of a drawback).
for AGP, get either a 7600GS or x800GTO (they're both pretty similar... x800GTO has better memory speed, but 7600 has more features).
Jam it back in, in the dark.