Pathfinder is great because of the three action economy in combat. Call of Cthulhu is good because of the intuitive system D&D is.... erm... Warhammer Fantasy Roleplay is a blast because of the randomized character creation method. Vampire the Masquerade is really fun because vampires hot.

Palladium games of any kind are fun because you liked them when you were 12, and also you can be a psychic elf with a suit of power armour.