I'm not vell versed in compressors, but you want the highest SCFM @ 90 PSI you can get. If it meets the minimum, you'll run out of air. Cut off wheels are air hogs and run a 60 gal compressor down in no time flat.
Check your tools, etc. to see what they require.
EDIT: I had one like this if IIRC. Even with a 5HP 60 gallon tank, it ran out of air with a zig wheel.
Ingersoll Rand Electric Stationary Air Compressor — 5 HP, 18.1 CFM @ 90 PSI, 230 Volt, Model# SS5L5
FREE SHIPPING — Ingersoll Rand Electric Stationary Air Compressor — 5 HP, 18.1 CFM @ 90 PSI, 230 Volt, Model# SS5L5 | 10 - 30 CFM | Northern Tool + Equipment
A two stage compressor is better than a one stage. However it is more $.