Don't get me wrong here, but... Beedle.
His hair, his voice, everything. It's not that he isn't useful, because he definitely is in both WW and SS, but I mean come on now. I've heard "THAAANK YOUUU!" enough times to make me almost have to mute the T.V. whenever I enter his store.
Windwaker was especially bad, when he gave 'awards' for getting so many points, or whatever? I put up with his cringe-worthy voice for more than any human should have to endure, and all he did was make funny faces at me? Unbelievable. The only thing that made it worth-while was that I got to bomb his ship after, haha!