I have a pug, and I think they are ideal apartment/small house dogs. They do sleep a lot, and aren't what I would call a hyper dog. Also they aren't the kind of dog that needs to have hour long walks each night.
My dog Pugsley lived in an apartment for the first 3 years we had her, and she was fine. She hardly ever barks, so that is a plus if you have neighbours very close by.