Originally Posted by jcarne
Tool usage will really determine this. In my case I bought a 21 gallon compressor and REGRET it almost anytime I do drilling in the garage. I love my Nova air drill but man I wish I had gone with a 60 gallon compressor. Those can even be had for around $600 new. I rarely even try to use my die grinder anymore because the compressor can't keep up, I do however still suffer through it when I need to. In short, there is too small and not too big when it comes to compressors in my mind.
I bought a 20 gal Northern Tool compressor from which is in adequate for painting, drilling or die grinders. If you want to do those things, get a 60 or 80 gallon compressor. If not, I recommend small and quiet like a California Air Tools 8 or 10 gallon.
My 2 cents.