what's the best... most space efficient way to store bikes?

we currently have a stacking two bike holder from supergo (like this once from performance) and the two mountain bikes hang from the ceiling... but that's a pain in the butt plus it's hard for me to get mine down cuz it's heavy and awkward...

the two remaining bikes just sit around the garage (one leaning on the weight bench and the other on a portable stand)

we've thought of getting something like a bike rack and have them lined up against the wall... sticking into the floor area more.. but that starts to take away from my workout space...

we've thought of getting 2 more of the racks like we already have...

and we've thought of using the hooks that hold the front tire and hanging them off the wall but up off the floor...

what do those of you with multiple bikes do for best management of space?

any suggestions or recommendations would be most appreciated!