I've got a pretty crappy, I mean simple airbrush, but I swear by it now. I use it for almost everything. I only use Tamiya's acrylics, so clean up is with water.
I don't have an air compressor, so I have to but the cans of compressed air. Oh, well, they last a good while.
I still go buy the Tamiya sprays for the body base coats, though. I use their primer, too. Good stuff. I think I pay $5 a can for the paint; $6 for the primer.