When choosing an air compressor your needs will vary depending on how powerful the air compressor needs to be for your needs.
For example if you just use the air compressor for painting or airing up tires then a smaller air compressor would be good enough.
However if you use air tools such as impact wrench etc then you would need a larger compressor that can build up more air pressure and hold more air in it's tank to operate the air tools.
I would recommend the belt drive types of air compressors as they are much quieter than direct drive air compressors are.
Either a Porter Cable or Craftsman air compressor are both good quality air compressors and I would recommend either of those as I've had good luck with both brands of air compressors.