The first one I thought of was a little more light-hearted than the war movies, but I've got to go with the scene where The Bride chops up the Crazy 88's gang in Kill Bill.

Actually, now that I think about it, pretty much every fight scene in the Kill Bill movies is over-the-top violent (the massacre at the church, the fight in the trailer house, putting and end to Buck, etc.) but instead of disgusting or horrifying me, they just crack me up.