What kind of compressor do you have? I was pleasantly surprised when I found out that the compressor I bought (oiled) was, in fact, way quieter than the oilless ones I had been around previously. It's quiet enough to cycle on and off in my basement garage with my infant son sleeping 9' or so overhead, and all that's between the two is an uninsulated floor and some carpet.
I guess all I'm saying is that the right pump won't make a ton of noise anyway- to the extent that it'll probably be the tools you're using that will irritate your neighbors more than the compressor.