I think the 9600 might be better than the 5500 , although it's pretty close.

I think the 5 series had some sort of issue that made them unfavorable but i forgot what it was. maybe it was just the 5900 ultra.

I have a radeon 9250 that is surprisingly good for what it is so i imagine the 9600 or 9800 would be pretty good.

PCI anything will be slow; AGP I'd look into a Geforce 4 4200 or Radeon 9800 for your Duron

Edited.

The best PCI card for XP/98 gaming is the Radeon 9100 PCI. Extremely rare, been trying to hunt one down for a long time. Its based on the 8500 (or 8500 LE) and it supports TruForm. Should be comparable to GF3 Ti200 performance .

I have been through FX 5200 and 5500 PCI. They are trash, useless for 98 gaming and not that much better under XP. I'd say avoid these. 64 or 128 bit, no matter. They perform terribly. I didn't expect much from them and still was disappointed.

For AGP, GeForce 3 Ti 500 or GeForce 4 Ti 4200 seem to be the best for your processor. Compatible with most games.