When I only had my 90's MTB I decided to hang it from the top tube on a pair of ladder hooks in the garage. Works great and it still stays there.

When I got my road bike, no way was I going to leave my shiny, brand new expensive bike in the garage. So I kept it in my bedroom on my side of the bed. Wife was okay with it.

Then when I got my wife's bike, we were just leaving it between the table and the wall in the eat-in kitchen (we have no true dining room). And now that I'm commuting every week I just put my road bike there, also. Road bike has no kickstand so it leans against the wall. Wife's bike has a kickstand so it holds itself up just next to my road bike.

Part of the reason for keeping the newer bikes in the house, besides security, is that there's really no room in the garage for anything else. We actually USE our garage for both of our cars. No way in heck am I going to junk it up to the point where one or both cars have to stay outside all the time.

I'm thinking I would like to get the Xtracycle conversion kit for my MTB one of these days. If that happens I'm not sure where I'll keep the bike. Likewise if I build up a dedicated commuter bike from scratch I'm not sure where I'll keep that one, either.

We have a 3rd bedroom but that's being used as a (very small) movie room with 1080p projector, 5.1 surround and all that jazz, so no bikes can go in there. Having a small house sucks.