I'd consider this as a starting point:
http://www.aircompressorsdirect.com/...sor/p5515.html
If you're planning on running any air grinders/sanders you need a larger tank. My Ingersoll-Rand 3.3hp 20 gal unit gets it butt kicked by a 2" Harbor Freight sander. I've yet to own a compressor for my garage that's had enough CFM or achieved the stated PSI rating. This or the 18.5 CFM unit is my plan.
Regarding dBA levels, the larger the tank the less they'll be running.
