I ran a conventional spray gun for shooting lacquers and oil based primers and finishes when doing cabinets, trim, or doors and roll up doors. I got out of painting full time, but my uncle (who taught me to paint) ended up setting up a small airless just for clear coatings.
Spraying finishes and getting good results is not a cake walk. It takes years of practice to get really good, even with an airless. You have to mask very well, or have the control with a gun to get very close without overspraying other surfaces, and it is still easy to go too far (such as spraying eves a different color than walls on an exterior).
For other air tools, 3/8" hose will usually work to get around a house. Cordless tools and great corded tools will often work better than air tools. The main tools I use air for, are impact gun, blast cabinet, angle and straight die grinders, blow gun, conventional paint gun. My old 5" milwaukee angle grinder is a beast and a 2 or 3 inch flap wheel on my 90 degree IR composite die grinder is great for small work and blending, but there was a gap for medium work where one was too heavy and the other not aggressive enough. A makita 4" angle grinder filled that gap. The body is small in diameter and it has decent power.
Look for an oil lubed, cast iron compressor, and 2 stage is great for keeping the pressure well above what is needed (smaller single stage can let your pressure drop too much).
For painting interiors, such as ceilings and walls, the right technique with a brush and roller will give you better results than a conventional or airless sprayer and there will be less mess. Most people don't know how to efficiently use a brush or roller so it takes them a long time and it is much harder than it has to be.
Bigger is better in air compressors. What other tools do you plan to use? There are a bunch of threads on the subject, on this forum. You can read for days.
