Scratches (including wheels)
Dents (in doors, bumper, etc.)
Rock chips in the hood front (hood area)
Check for windshield chips/stars?
Last oil change
Last change of belts, seals, fluids, etc.
Last tire change (Tire tread life)
Look at the histroy (they'll show you)
Ask about anything major, or whatever concerns you
Post some pics (inside/outside/under the hood). I'd LOVE to see it.