Sometimes I wish there were more video and computer games in which one could play a Khornate-style of character. One of the big disappointments I had with WAR (Warhammer Online: Age of Reckoning) was that the playable Chaos faction was Tzeentch only. It was especially annoying once we were able to see how cool the Khornate mobs and areas in-game were. Ahh well.
At least it looks like the playable Chaos characters in Dark Millennium will be Khornates. Old news in theory, but still very exciting. Outside of the Dawn of War series of games and the occasional game like Darksiders, there is not too much out there IMO.
Age of Conan can come close at times, save for how petty the questing and such could feel at times. Great combat system in that game, a shame it suffered from various other problems. WoW, alas, has never really felt like it had a comparable option; perhaps the Death Knight Hero class, but I have never played one. The basic Warrior class certainly doesn't feel right.
Certain styles of action brawlers sometimes can capture part of this feel. The upcoming one where you play as a Space Marine looks pretty cool IMO, even if the playable option looks to be Ultramarines. Heh. Perhaps the PC version (if there really ends up being one) could end up with some mods that allows one to change their appearance to other chapters.
The recent Fallout games (3 and NV) were pretty darn good in this regard. There were a ton of fun Warhammer-themed mods for Fallout 3, a number of which got ported to NV pretty swiftly. Easy to do for just the textures and graphical mods of course. Slightly harder to do something like Enclave Commander naturally.