I have awesome neighbors. Been recording in my apartment for about 5 years now. Drum kits, guitar cabs, bass rigs, choirs, you name it. Of course it helps to be extra friendly with them.
I've always made an effort to make my closest neighbor aware in advance of any drum sessions-- those bother him the most. My other neighbors don't seem to hear anything. Maybe because we are really close to the freeway? There have been times when I've said "Yeah we finished recording drums yesterday" and they say, "Oh really? We didn't even hear it!"
thumbsup
If I ever have to move into another apartment I will definitely scope out the neighbors and chat with them before I sign anything.