Vex goblins and hobgoblins when you got them in the chest. Oh yes, shooting fallen on the head is cool, I take pleasure on blasting canal to hell, and those dumb floating, purple balls explode brilliantly...
But there is something about an entity which explodes in a cloud of white goo when you shoot it in the stomach which just screams "programmer was smoking something when he thought this one up."
Really, I know an artist who could do an awesome "you're covered in Vex goo" cartoon. Maybe I should drop him an IM.
Favourite death animations anyone