A friend had a window AC he really liked, designed so that the window closed to an inch or an inch and a half from where it would close without the AC.
He said that most of the noise was on the other side of the window, so it was quiet.
Do they still make this design? It's sounds like a good one.
It either broke, or he moved and had to leave it behind. I'm not actually looking to buy one, and neither is he, I think.