I agree with Jim, you will want a 2-Stage 5HP minimum...such a a Quincy QT5, Eaton, Saylor Beal, or Champion.
For heavy sandblasting I would go with a 7.5HP.
I would also recommend turning down the pressure switch to less than 175-180 PSI, you will find out the compressor runs better set to 140-150PSI maximum. You still get the advantage of the 2-stage efficiency but the compressor isn't working so hard near the end of the fill. That last 25-30PSI in a 2-stage compressor trying to get up to 175 or 180 is slow because it is fighting against the tank pressure.
You will also find the noise with a quality compressor to be much less than others. They often spin the motor at 1750RPM instead of 3600RPM.
Whatever you do, do not ever get an oil free compressor.
---Aaron