It's got to be the loud and very annoying preacher guy in the middle of Whiterun. I need to just kill that ass and pay the bounty.
OMG serious? I was just thinking of posting a thread that he is my favorite insane prophet of any Bethesda title so far! Kind of a tradition you know. Oblivion's prophet ranting about the end of the world, Fallout 3's insane prophet of Adam, but this guy takes the cake for sure!
"Sharing the heavens, with us? With man? HA! They can barely tolerate our presence on Earth!" - Epic
Anyway, most annoying NPC... got to be that stupid dog from the Clavicus quest, just because every time I stand still he runs up and sniffs my butt and nudges my character forward over and over like five feet. I had to save the game just so I could beat the tar out of him. Annoying NPC with essential flag is annoying!