Best NVIDIA AGP: GeForce 7950 GT (rare)
Best NVIDIA PCI-E: GeForce 7900 GTX
Best ATI AGP/PCI-E(?): Radeon X850 XT Platinum Edition
The story of the newest NVIDIA drivers for 98SE is more interesting than you think, I might do some investigation with them.
I have a GeForce 7900 GTO PCI-E (underclocked 7900 GTX made by MSI and EVGA exclusively), and it works fine under 98SE, but it hangs the system sometimes, because of the 512MB VRAM.
In general, I really do not like Forceware 98SE drivers in general. I like older drivers like 45.23 much more. Perfect match for a GeForce 4 Ti/FX 5950 Ultra card. I think those are the "best" non-Voodoo GPU's for 98SE. I don't see a good reason to have GeForce 6/7 for 98SE...unless there's a 98SE exclusive game that requires Shader Model 3.0...any out there? 😀 Or if you want to try to run newer games with the help of KernelEx like Fallout 3 or The Witcher 1 (they do work, I tried them 😀 ) or even GTA IV like me...no success with that one so far 😜 I know people want the best, but with 98SE, best is not always the best 😀
About ATI, I think their drivers might actually be more interesting/stable than the NVIDIA ones. Maybe not for DOS, but still. And there are no hacked drivers to worry about with ATI, everything runs fine with the official Catalyst 6.2 drivers still available from AMD's website. Also, all X850 XT PE have only 256MB VRAM, which is the max what 98SE handles without patches, so no system hangs will occur. I do not know if the PCI-E version of X850 XT PE work under 98SE, AGP does definitely. I would not scratch off Radeon's just yet. I've used their drivers and they worked fine, with fewer errors than Forceware ones.
I'm just blabbing based on my relatively short experience, I might be wrong.