+1 for the hospital. Proper survival horror feel to it.
There was also a level in between map locations where I could look for supplies. In this case, there were no zombies. I could hear them off in the distance, but couldn't see any walking about, just loads dead on the ground. It was really spooky, as if maybe it was a glitch - but it wasn't - one or two eventually appeared.
Obviously it wasn't the best level in the game, but it was an abrupt change of pace that worked really well.