I'm running Ubuntu and I was very happy to see the legacy drivers package included in the recent Breezy release. Unfortunately, after I upgraded I got accelerated graphics and an occasional reboot.
When I used to run Mandrake, I had this problem until I started compiling my nvidia complements at the 2960 level. I can't get that module to compile under Ubuntu.
Take a look at my Xorg.0.log here http://onedrous.org/ww/nvidia/Xorg.0.log
My lspci output:
0000:01:00.0 VGA compatible controller: nVidia Corporation NV5 [RIVA TNT2/TNT2 Pro] (rev 11)