Something like this would be a minimum IMO if you plan on using air tools a lot, especially cut-offs, drills, and sanders.
http://www.aircompressorsdirect.com/...ssor/p591.html
This appears to be a decent "budget" choice:
http://www.aircompressorsdirect.com/...ssor/p855.html
My Ingersoll Rand 3.5 hp 20 gallon can't keep up with a 2" disc sander.
