If I had my Druthers, I'd have a much larger compressor than I do. I've got a 2.5 HP 25gal "portable" Sears compressor. It's a heavy duty home compressor. It gets the job done but, I can't paint < cup gun> and run nailers very well at the same it.
Porter cable, Campbell Hausefeild < sp?> either is a good choice. I'd like to have an upright 200 gal 3 - 5 HP also seriously look into plumbing your shop with 3/4" gas pipe, and having regulator stations spread around.
A shop I worked at had this setup where they had taken little peices of ply and mounted a regulator and dryer on them. they had the shop plumbed and the pipes came down to disconnects all over the place. Each regulator setup had a short tail to plug it into the disconnects. The Whole system was charged at the
compressors full pressure, 180 psi I think, then you could regulate at the area you were working.