Gloves to wear while riding and at least one disposable glove in with the flat repair kit- cuts down on the grease getting on your hand when removing the rear wheel. Possibly throw in a Grease Monkey Wipe as well.

The most important thing that I couldn't make do without after getting it was my floor pump. I got like 3 pinch flats in like a week relying on the air compressor at the c-store.