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!