I know I'll use it to make vegetables, both fresh and frozen, and to reheat leftovers and defrost frozen things, and probably to make some convenience foods. My mom makes iced tea with hers, and that strikes me as useful as well.
I have a microwave cookbook (okay, I have two, but they're the same one - the one my mother-in-law gave me when I was first married, and the one she just gave me in honor of the new toy because in twelve years she forgot she already gave it to me. The only difference is that the new one is paperback.), but it's from 1987. Anyway, I'm not really a cookbook user.
Does any one do any sort of real cooking with them?