There's the Quincy 325, then there's everything else...
I doubt anyone here would spring for a new one, but it really is the absolute best compressor you can buy, anywhere, anytime.
Good runner-up would be a Champion, DV Systems (DeVair, OLD, CAST-IRON Devilbiss), IR Type 30, Kellogg, Curtis Masterline, Gardner Denver, or any TRUE 5hp industrial quality unit. NONE of these will be cheap new, but with the economy the way it is, you might find something going fairly cheap from a shop closing down somewhere. You would have to spring for a decent single phase motor, and have the electrical service and a mag starter to run one, but any of these units would be heirloom items to pass on to your grandkids.
For the most part, the older units are MUCH better than anything you will get at the hardware store. If you could find a nice Emglo cast-iron twin on a 30-60 gallon tank, you would have yourself something really nice.
BTW, if you run it with a gas motor, you will have to de-rate the pump by 50%, or buy a pump that puts out half the cfm (i.e. a 2.5hp pump with a 5hp gas motor) since an electric motor has much more torque at low rpm than a gas engine.