I've always wanted to have a "shop" - a detached space, like a pole barn, where I could work on projects and store things. A lot of people I know in my life have such an arrangement and I'm occasionally jealous.
These days, I live on a large enough piece of land that I could pretty easily construct such a building. However, I've stopped myself because I've realized that I just fill up whatever space I have. If there's room to store something, you can just put it there and plan to deal with it later (of course, later almost never comes). I'm the type of person that has a hard time getting rid of things that I paid good money for or that have sentimental value, and as I get older I'm increasingly envious of those people who have less hesitation about throwing stuff out. For some things, selling is an option, but that has its own set of hassles.
I have a garage like you that has one stall full of stuff - family bikes, tools, a table saw, grill, etc. Stuff that we do use, though some of it is probably not used enough to justify the space it takes up. Every time I clean up the garage now I try to make a point to get rid of some things, though all that does is tend to break even with the new stuff that inevitably gets added.