stay well away from ebay screens. all those brands you've never heard of are really poor quality and the ones you have heard of have no warrenty backup. If I was parting with over 500 notes I'd want some reasurance of a warrenty.
gauges... oil temp, oil pressure, water temp, vacume, air/fuel ration, fuel pressure, voltage, ammeter, exhaust temp, inlet temp, fuel level and a clock...