I was having a similar issue (freeze at splash screen), but set:
NvAGP "0" which allowd me to get into X. GL was rather slow however.
I noticed this morning that the machine was frozen, and when i got into work i could not ssh and reboot. I guess there's something to be said about "if it ain't broke...". I'll backtrack to earlier drivers and see if i get better performance.
Asus v8200 ti200 (GeForce 3)