A lot of great advice already given. In my view of a good home unit it would be belt driven as it allows repair of either down the road if needed. It would NOT be
oil-less, get a cast iron 2 stage pump. It would be an upright for space and configuration reasons. It would be a 60 gallon at the minimum. It would be a 220 volt with HP able to deliver 15 CFM at 110 PSI.
It would be located outside the work area but covered from elements with just a roof or overhang maybe or enclosed but plenty of air flow. I used an old auto air cond. condenser mounted on output line then into a water trap then a ball valve to turn on/off for line repair if needed. The AC condenser cools air a ton to separate water before it gets into system, well most of the water anyway. I also used a out of date propane tank I got for 20 bucks as an extra holding tank (about 20 " diameter and 5 foot tall) I mounted it upside down so valve was at the bottom for drain reasons. This is my home unit but can run about anything a home builder would need. enjoy!!!!!!!!!