Air compressor
You want the most CFM with the biggest tank and HP motor you can afford.
BUT, as I am SURE toolmanmike will have in his write up, CFM means nothing unless it is rated ad a PSI ABOVE zero. I use 90 PSI as a standard. In other words I look for the highest CFM @ 90PSI with the biggest tank and most HP in my price range.
MANY compressors are rated with a CFM rating @ 0PSI. That's worthless as tits on a boarhog.