When my wife and I moved into our house 8 years ago, I claimed the downstairs bedroom. Can't really call it a "man cave" if there's no TV and a lot of books, so I call it "my study." Sounds better.
Here's the workbench:
And my collection/stash, mixed in with my RC models...
The other side of the room is my desk, currently a mess as it's my work-from-home office.