Ian's is fun, they make all sorts of crazy pizzas. The mac and cheese pizza is a good one to eat after drinking a few beers on state street. When in Wisconsin right?
My colleagues all enjoyed eating Ians frequently and I found myself gravitating towards their pepperoni pizza, which is delicious. I've also heard the salads are really good, I wanted to try one when I lived in Madison but it was to hard to resist the pizza temptations. :P