Anthony, I'm now at 10.8. Haven't updated to 10.8.2 because 10.8 is stable for me - no glitches at all so far.
I'm not sure when it was introduced, but somewhere along the line Apple, presumably in an attempt to address problems just like this, threw in a kext file called AppleGraphicsPowerManagement - an extension which controls the power-saving features of graphics cards and tells them when (based on the idle percentage of the computer's processor) to switch to different power-saving modes. This kext overrides the BIOS settings, effectively unfixing the fix I'd found (way to go, Apple). As far as I can tell, all the problems we're seeing relate to the card attempting to switch to and from different power-saving modes.
I thought trashing the kext might work - it didn't. Still crashes galore in 10.8.3. Then I thought I might be able to tweak the values of the kext as layed down in its Info.plist file so that the card wouldn't switch modes at all (all the information on how to do this comes from the Hackintosh community - they're the only ones interested in the inner workings of OS X these days, Apple engineers included). That didn't work either and I got tired of stuffing around trying to fix a problem I shouldn't have to fix and simply went back to 10.8.