Yeah, postal 2 is horridly dull. I tried the demo a few times, but the fun wears off in about 5 mins.
There was an adventure type game that came out a few years ago. I forget the name, but it bombed...anyway, it had torture, rape, canibalism, and God knows what else. A friend of mine had it, but said the gameplay was shit and the violence was stupid in the context of the story.
The best violent game, up until about two weeks ago, was GTA3. I say that because I just got Vice City the other day, and it's even better.
Anyway, if you just want straight-up, realistic gore, go for Soldier of Fortune 2. With a decent graphics card, you can actually see bullets punch holes in people. It's a so-so game, but all the shooting is fun.