You get the (non-working) option for 8xFSAA when you use the beta V5 6000 drivers. Supposedly, the team at 3dfx leaked them at some point or something.
Anyhow, I personally run a V5 5500, and I've tried all kinds of different drivers and bios updates and blah blah blah. Honestly, I've yet to see any driver or bios give a significant increase to my framerate (+10fps or better). Getting 3-4 more FPS doesn't make a break any game.
In the end (right now), I've just taken whatever glsetup gives me. Whatever version of the drivers it dishes out (I've never cared to find out) seems to be the most compatable, as I rarely have crashes related to video. Framerate is as good as any of the other drivers I've tried, so I don't see any real reason to change.
On a side note to Biased turkey, a friend of mine runs Win2k with a V3 3500 and seems to have only a few problems. His biggest issue is related to Tribes 2, but I'd bet that's due more to Dynamix sucking ass and releasing bad code than it is to bad drivers, considering that the same problems happened in Win98SE. Only difference is that in Win2k, sometimes he can close Tribes 2 without having to reboot.