Guys, seriously?
Postal can be violent, or it cannot, it absolutely depends on the player.
Same with GTA, if you kill thousands of Civilians, it's because you wanted to(or you're a 12-year old going through puberty and playing the game[which applies to the usual Xbox360 player))
No Russian, same thing as GTA, just in first person (the 12year old part).
My nominees would be Thrill Kill for PSOne (youtube it, if you're interested).
Thrill kill was just so twisted, I'm not surprised it went by unpublished by EA (though it is still avalaible if you look hard enough).
Second place for me would be Manhunt 1/2.