Oh yknow this one time, where it went slow-mo and the bullets could be seen and then the enemy splattered and it was awesome! xEverytimeVATShaseverbeenused.... <_<
VATS is very very very repetitive, the fun and cool factor of it wears off after the 5th time I used it in FO3.
In NV I use it merely to cheat a shot when killing the Mojave Chapter, other than that I never use it.
So anyway, favorite moment, it was in The Pitt, when I used a sniper on the sniper on the bridge, watching the bullet in slow-mo as it splattered his head and then fell down on the bridge was kinda "cool" I guess.
VATS+pointblank+shotgun+feralghoul is also very satisfying.