Yep, you'll definitely want a 30 gal tank to run grinders, sanders, etc. that require a lot of CFM. Nail guns will be fine with the little one - just use a lot of hose to get from room-to-room.
I have a 30 gal industrial compressor tucked under my basement stairs. I ran 3/4" air line to my workshop and up to my garage. Then I wired 3-way switches to a contactor so I can turn the compressor on/off from either location. I've got about 250' of hose...I can reach anywhere in the house and yard with that. Works great!
Just stepped up from a Craftsmen 30 gal to an Inger-Sol Rand Vertical 11 HP max output! NO COMPARISON... Good advice offered above! My advice is spend as much as you can afford up front. My last compressor is still going strong (almost 15 years old..) Point being your going to have this thing for a while and you never know whats in your future. Hose is cheap just figure out what your use is going to be and purchase on that requirement!
(JINKSTER @ Jan. 10 2007,17:28) The specification to measure and judge by is the compressors "C.F.M. Rating"...(cubic feet per minute)...and then make certain that you buy a compressor capable of keeping up with the air tools you wish to use CFM requirements for use..
Agree with you 100%, on top of a filter to catch nasty shid, you might invest in an automatic drain to keep moisture down or go all out and get a dryer. My little one has a drain. Opened it last night after reading your post and got very little moisture.