[MikeSid]

It all depends on the tools you intend to use. Burst tools like nailers and impact wrenches require less CFM of air than continuous use tools like HPLV gun, grinders, sanders, etc.

For burst tools (and filling your tires, etc.) a little Dewalt (made by Emglo) or Thomas compressor works fine and is pretty compact. I've used both and while the Thomas is a little loud and heavy it's a fine compressor. The Dewalt is relatively quiet.

For continuous use tools, a 2 stage compressor is recommended. These can get pricey. But if space is a concern and you need to run sanders, grinders, etc. you'll need a two stage because nothing else will keep up with your air requirements and size constraints.

Basically, pick the tools you'll be using, find out how much air they require, then pick a compressor that can provide that. Don't rely on horsepower ratings. That's virtually meaningless for compressors and is often the suject of marketing "exaggerations".