Air Compressors can be divided into several categories:

Reciprocating
Rotary Vane
Rotary Screw
Air Brush
Portable

You will of course need to choose the right type of compressor for the job you intend to perform, for instance if you are aiming to use the compressor to blow up balloons or footballs then you wouldn't want a compressor which discharges air at a higher rate, for instance using a 40 HP compressor for this would over inflate within seconds and have undesired consequences.

So when considering which compressor to purchase you'll need to know what sort of capacity you are looking for (its ability to push air at a certain flow). Also consider that choosing a compressor too small for the job will mean that it never keep up with the demand (the outflow requirement would always beat the ability for the compressor to push the air required) so the result could mean that compressors which aren't designed to cope with heavy duty would run at full capacity until they justbreak.

So you will need to consider your requirement for Compressor Capacity (for pressure and flow).

VANE AIR COMPRESSOR
Vane compressors are best for use as 'air tools' as the technology allows for prolonged use (you may see these types used in road works or building works where the power is provided by diesel or propane). Vane Compressors are mostly used for hobby trade, vacuum and pumping.

RECIPROCATING AIR COMPRESSOR
The most common form of compressor at home is the Reciprocating (piston) air compressor, these are low cost to purchase, but can have high operating cost. So if you are planning to use a lot of air, then consider another type of compressor, it may save you money over a longer period of time.

ROTARY SCREW AIR COMPRESSOR
Rotary Screw compressors are said to be more suitable for industrial uses. Consider a rotary screw air compressor if noise is a concern. Also if your thinking about the higher horsepower units then many manufacturers state that this type of compressor has least maintenance and lower running costs.

PORTABLE AIR COMPRESSOR
You may also of course not be in a situation where you have air mains, or there may not be any other forms of power to supply to your compressor, so you will need then to look at using portable compressors.