I use a Craftsman 1.5hp, 3-gallon compressor:

http://www.sears.com/craftsman-3-gallon-horizontal-air-compressor-with-hose-and/p-00915310000P

I picked it up, because it can drive either an airbrush or air-powered tools.  It's noisy, of course, but that wasn't a problem for me.

My airbrush is a Paasche VL.  So far, the combination works pretty well.