Usually ice cream, especially if I have a sore throat.
When I'm sick and finally work up an appetite, I try to eat something really flavorful. Maybe some Vietnamese food or some sort of BBQ dish. Then it's back to the old ice cream. Throw a banana in there and that's about the one thing that'll always go down well no matter what. I keep an emergency bucket of ice cream in the freezer just for when I get sick lol