Some of the aforementioned film/scenes are more gory than violent. Rape is pretty much the ultimate violence as has been atested. Rape and the killing or torture of innocent, defenseless people is the most violent scene to me. In addition to the previously mentioned rape scenes:
Schindler List - the executions and shots from the balcony.
Sopranos - Ralphie beating up the who-wah.
Deer Hunter - the Russian Roulette scene.