Depends on the size of your group too, nuclear war and illuminati are hoth better with 4+ players.
All 3 games are essentially about screwing people over so you also need a group that'll play in the spirit of fun.
Illuminati can take a while to play, nuclear war is generally fairly fast, munchkin can potentially reset so it can be either fast or slow.
Personally I have a soft spot for illuminati (any game with rules for cheating is a win in my books
Nuclear war is a lot of fun especially in a larger group its revenge mechanic means even if you go out you do it in style ...
Munchkin is silly fun but if you're looking for any kind of depth it is just a cardgame albeit with a level of strategy (and bastardry)
All 3 are kimda silly but illuminati is the most serious and the most "gamey", nuclear war has decent strategy but is very light (fast anf unpredictable) and munchkin is very luck of the draw.