OK, here's my run down...
most consistently violent.
spartan warrior, really great, lots of blood shed, fighting with swords, decapitations etc hacking stabbing chopping, and all done so quickly and consistently that really you seem to forget it's happening... non stop button bashing, easy, yet difficult, great game.
Violent but boring:
Manhunt, there is really only a handful of times you can bottle someone/strangle them with a carrier bag before it just get boring, also the creep around and try to stay hidden aspect of it is shockingly bad as well, the whole theme of the game is that you're in a real life snuff movie and fighting for your life.
the best bit about the game is the packaging, it comes packaged in a film style like catalogue order with a dodgy book advertising snuff movies...
really when the best bit about a game is the packaging you then know that it's properly wank.
am I disappointed that I won't get to play Manhunt 2 - Hell no!
Immersive disturbing game:
Eternal Darkness: sanities requiem.
it's a game cube game, you play the part of various humans throughout time, in a war between gods. there are parts that are really slow, but then there are shocking things that happen, like things that flash up on the screen really fast. (like a body in a bath filled with blood).
most funnily violent:
can't remember the title, but I played it on Xbox, it's a very old game, basically you get to play the part of a freedom fighter in some sort of revolution, it starts in a shopping mall, where there are random weapons on the floor, you can also pick up objects, break shops and beat up the guards,
you can beat up the public but you'd loose points for that...
anyway, it's funny violent because you get to lob TV sets at people and hit people with bats, and when all else fails you punch and kick your way out of trouble.
IMO gta isn't actually that violent, fair enough you steal rob gun down and run over people... but that's just a day out of ordinary life isn't it?