I just searched craigslist in your area. There are plenty to choose from. Direct drive and belt drive. Vertical and horizontal. Once you have one, you may wonder what you did without one and may hate yourself for going cheap and small. Belt drive will give you the most life but will put atomized oil in your line. The only disadv with this is when it comes to using your compressor for painting. An impact wrench will use 4-8 CFM. This is not a lot. When considering the tank pressure, most you will find are 125 psi, while most tools run on 90 psi. So run your tank at max pressure and buy an in-line regualtor for ~ $20 and set it at 90 psi. Some Sears air compressors get up to 225 psi. I think these are mostly their vertical, 2 stage compessors. CFM matters when you start running cutoff wheels and sanders.
A note about stages. Some compressors will boast twin cyclinder. This not the same as two-stage compressors. Twin cylinder means that the compressor simply uses two cylinders to compress the air from 14.7 psi (atmospheric) to 125 psi. Two-stage means that one cylinder takes it from 14.7 to 90 psi, discharge to the second stage, where it is pressed up to 125 psi or higher in most cases. By using two stages, the air compressor operates more efficiently and usually results in a higher CFM rating. This also produces less heat, which means less wear on the compressor and most importantly, less condensation in your tank. This is why it's important to always drain your tank when your done using it. A neat feature I've seen on newer compressors is finned discharge tubing from the compressor to the holding tank. This helps to cool the air before it gets to the tank.
If I had to buy one new, I would buy a belt driven, 30 gal, vertical compressor that runs on 120/240. Northern Tool sells one here: http://www.northerntool.com/webapp/w...1705_200311705
Vertical-Takes up less real estate in the garage
120/240-wired for 240 -> draws less line amps -> cheaper to run
wheels-can be taken to a job site
cast iron belt driven-will outlast a direct drive
I ended up buying one on ebay-60 gal, 240V-because the price was too good to be true ($150). Never regretted it. Good Luck