So this might be somewhat big for Halo 2 Vista but I forced enabled v-sync+FXAA with the new Nvidia drivers and not only does it look great but it is FINALLY playable with the KB+M
FXAA shot
FXAA will only blur up your screen as opposed to the actual built in AA. Deferred Engines and games with lots of alpha and poor anti-aliasing are the ones you gotta use FXAA on.