I like pretty much all toppings. I don't feel a burger is complete, for example, without lettuce, tomato, onions, ketchup, mustard, and mayo. I'm not that picky a eater, but things I do dislike (cilantro for instance, I tend to dislike with a vengeance).
I feel that most food isn't completely without a combination of all of those things (spices, vegetables, meats).