For model-making (airfix type of thing) I use my trusty Iwata sprintjet compressor as I only need around 15-20psi for relatively short periods. Not surprisingly, it couldn't cope with the higher prolonged pressures the bodyshell paints required (40-50psi) so I acquired one of these ....
http://www.machinemart.co.uk/shop/pr...compressor-324
Probably a bit over-kill, but it certainly does the job!