I voted for Kaepora Gaebora. His speeches were way too long and it's especially annoying since I've beaten the game before and already know where to go and still have to sit through his long explanation. Then if I'm just repeatedly clicking to get through the dialogue, I always accidentally click "No" when he asks if I understand and have to sit through it all again.
Navi wasn't too bad, but she could be a little annoying when she randomly tells you useless, obvious information that you already know such as "This door is locked!" IT'S SO OBVIOUS!
Ruto would have been my second choice. She's so stubborn, selfish, bratty, childish, spoiled, lazy... Need I say more?
The Mailman from Twilight Princess wasn't annoying at all. In fact, I found him hilarious and was one of my favorite characters.
Tingle.. I don't hate him (See my avatar). There's nothing wrong with being weird. I'm EXTREMELY weird so I guess he fits my personality.
the only time I wasn't fond of him was when he made you pay money to read your charts in TWW. Other than that, I thought he was hilarious!