I suppose it depends on the situation:
If I just want a piece of fruit, I'd go with pineapple or an orange
If I were to add something to a beverage, it'd have to be lime (I am rather crazy about lime)
If it's something I have to grab on the go, it's gotta be grapes or strawberries
EDIT - Now that Optimus has reminded me - Kiwi!
I think that covers the favourties I have in mind, at the moment.