Morokei said something very similar as well.
I duess it depends on how you define Douchebaggery. A lot of the prior responses seem pretty obvious in context, while others didn't give enough specifics. I voted Ragnar the Red because of his actions in the song about him. Pretty much the only one in the Bard's repetoir given as a Ur Example of Douchebaggery. You pretty much have to be trying to top that.
Ragnar the Red (Played by Rob Schneider.)
Oh there once was a "Hero" named Ragnar the Red, who came riding to
Whiterun from olde
Rorikstead.
And the braggart did swagger and brandish his blade, as he told of bold battles and gold he had made
But then he went quiet, did Ragnar the Red, when he met the shieldmaiden Matilde' who said;
"Oh, you talk and you lie and you drink all our mead
, now I think that its time that you lie down and bleed"
And so then came clashing and slashing of steel as the brave lass Matilde' charged in full of zeal
And the braggart named Ragnar was boastful no more when his ugly red head rolled around on the floor.
Da Derp Dee Derp Da Teetley Derpee Derpee Dumb