The most important quality in any good sauté pan is a heavy, solid bottom to ensure heat distribution. It is helpful to have two good sauté pans. One with sloping sides for sautéing things that should be tossed, and one with straight sides for larger pieces of meat or seafood that require turning rather than tossing.
If you can, try to have a couple of sizes. If you sauté too much food in a smaller pan, you risk making a mess and too large a pan for the amount of food can lead to problems with burning.