well, about the only thing I've found that I don't like to cook in my new carbon steel pan is eggs. More specifically, Egg Beater's style no-fat egg substitute. I generally eat those because I can eat more for the same calorie load.
They're made pretty much entirely from egg whites, which means that they are all protein. No matter what, no matter how much fat I use, they stick for me, so I've gone back to a non-stick pan for my weekend breakfasts.
Everything else I've cooked in the carbon steel pan, though? Turned out great.