I'm finally getting around to upgrading my compressor from the little dinky one that came with my airbrush. Went to Home Depot this AM to see what they had. Several 4 - 6 gallon ones look like they will work pretty good. Before I take the leap, I thought I'd ask to see if anyone has any tips or suggestions so I don't end up spending good money bad.

I have always just used the Porter Cable pancake compressors! They work great! Bonus...they come with a brad nailer!

i would get something with at least a 12, 15 gallon tank. The little ones work good but they will cycle on a lot and thus be noisy. I can fill up my 15 gallon one, shut it off, and paint all day on maybe 2 fillings and mostly just the one fill up.. Sears has some very good ones and not that expensive, look for sales. I prefer the oil ones too as they last a lot longer and are a little bit quieter. Just my 2 cents.

You answered the question I forgot to ask and taht was about noise. I have no separate space to keep a noisy tank in, so going larger seems to make some sense. I've also read that I may need some sort of filter attachement to catch condensed water in line between tha tank and the air brush. Probably explains why I've gotten the occasional splatter of water mixed in with the paint.

yes a water trap. I have one and have never found a speck of water in it, but good insurance. I also run a 50 foot hose too even though the machine is only 20 feet away. I think Mike, fishingfreak, told me several years ago that a longer length of hose helps regulate the pressure better. Never been a problem for me so I guess it may work. Also draining your tank after every session keeps the tank from rusting away. That is about all I can tell you. some may be true and some may be pure horse hockey

Is the water trap a "standard accessory" on most compressors?

I've got a small Makita and like it just fine. When it runs it only runs for a minute or so and isn't overly obnoxious.

I use a porter cable pancake also ..so far it's great
Used brad gun to make spray booth
homies had 'em for a good price maybe $149 last year