In our one bedroom apartment the girlfriend and I have 2 bikes on a rack in the living room, one bike leaning against a bookshelf on the other side of the living room, one bike in a corner in the bedroom (which sticks out so far we can only open the door about 60%) and a final bike on a trainer next to the bed. Except for blocking the bedroom door we really enjoy having all of the bikes around; if you get a nice looking rack you can use the bikes as a type of decoration.
We're talking about getting 2 LHT's, and I might get a mountain bike, so we may need to move into a bigger apartment soon.