At the moment, I have a special hatred of the tiny extras that come with Power Rangers - the little tiny ones that peg into their belts. Our boy takes those off and they are currently in a pile near my bathroom sink, just waiting to be knocked into the drain by a cat.
In general, I think my least favorite accessory was the Playmates Star Trek phaser that had the energy beam coming out of it. Those just never looked right to me. I think I disliked those even more than the neon-colored accessories that you'd sometimes end up with.