Kiwi is my favorite as long as someone else is preparing it. I also love blueberries and blackberries-really any fruit expect grapefruit.
Since I discovered the joy of banana whip, I've been leaning toward bananas lately, too. It really calms that late-night craving for ice cream, and apparently helps me sleep, too! I've heard there is tryptophan in fruits that help you get to sleep and stay asleep- something my overcharged brain needs when I get home from class at 10 and have to go straight to bed to wake up at 5:15.