Now, you can submit a real person if you like (yes, I know, a lot of 'Jack Thompson' is going to come up in this thread), but at least try to at least submit a game character too.
I think one character who sums up the phrase 'douchebag' quite well is Kent from Dead Rising
The first time you come across him, he comes across as a self indulgent little prick with a shrill, high pitched voice that just makes you want to stab him in the voice box with a machete. Now, a player in their right mind would skip his highly annoying photography mission he gives you (taking pictures of THIS douche? No thank you) by clubbing him over the head with a baseball bat until he stops twitching and all would be well. Now, if one decides to partake of his incredibly irritating mission of taking certain snapshots of high point value, there is a good chance he will get to laugh at you in the most annoying way possible if you screw up then prance away never to be seen again before you can disembowel him.
I'll spoiler the rest for minor mission/story spoilers, but they aren't that important.
Now, if you get the pictures he wants, he will throw a tantrum, once again prancing off after telling you to meet him later on. Once again, if you didn't club him to death earlier you will probably regret it as if you make the meeting a second too late, the douchebag has tied up/kidnapped an innocent survivor and taken a snuff shot of them being molested in the ear by a zombie larvae. If that wasn't bad enough, he then pulls a gun on Frank, orders him to strip his clothes and chains him up by the neck so he can take pictures of Frank being mauled by zombies.
All that happens if you make the meeting on time is you get the give him the beating he so rightly deserved at the start of the game, well, you get to save one extra survivor, but if you killed Kent earlier he wouldn't have been able to kidnap this guy in the first place. Sure, one could say that if Kent didn't kidnap him for Frank to save, the survivor may not have... well, survived, but still, if he could of gone through his life without meeting Kent the Douche I think he would have died a much happier man. Yes, I declare that being eaten alive by zombies is a more enjoyable fate than meeting Kent.
There you go, a game character with NO reedeming qualities who's purpose in life only serves to make everyone else miserable, the only positive confrontation with him involves him beingbeaten to a bloody pulp in the most entertaining and satisfying way possible.
I haven't played too much of the game, but Steve Burnside from Resident Evil: Code Veronica X certianly fits the criteria of 'Douchebag', as deligtfully illustrated in this quite amusing Let's play adventure http://fromearth.net/LetsPlay/RECV/chapter1.html
Lifted from the let's play, videos that show how much of a douche this guy really is
The first encounter - http://fromearth.net/LetsPlay/RECV/Videos/recv2-1.avi
Claire's expression at the end just sums up exactly what she is thinking after saving this douche's life and putting up with his sass - http://fromearth.net/LetsPlay/RECV/Videos/recv5-2.avi
So, what other characters (or if you like, real people) in gaming do you find to be insufferable little twats who only deserve to be put through a wood chipper?