I've airbrushed for many years. Brushes: Paache is good-especially the top of the line; Aztec OK if you like the grip; IWATA is my hands-down favorite-I've got 6; built like a tank and very precise tools.
I generally, dislike diaphragm compressors unless it's a one shot need: hot and noisy, sometimes irregular airflow and definitely hard to regulate. For studio work something like the Badger Millionaire line, silent compressor is excellent. Frankly a good shop compressor (EX: Sear/craftsman) and a solid regulator might give better versatility. I've got a five gallon craftsman in the garage that I use for--well--anything that needs a shot of air! It's loud, but it will drive nails inflate tires, blow the dirt off the dog and shoot paint. It's perfect for blowing a gun dry too.
You may also need a water trap--depending on your location and humidity.