Thought of another one for the man cave: the B-52 cockpit from Dr. Strangelove.
Peter Jackson has one Kong armature – he did a stop motion of that vs his pterosaur* armature. It is probably on the DVD extras – I couldn’t find it with a quick search.
Brian
*Pteranodon? pterodactyl ?
A sandman’s Weapon from Logan’s Run. The prop contained a carbide lamp mechanism, and shot real flames from the muzzle.
I have read that they were quite tempermental, and frequently burned the actors. I would probably limit myself to imaginary flames when I played with it.
1973 Ford Falcon XB GT coupe from Mad Max
Here it is:
Thanks! I could fit that in my place easily. Hmmm …
Seriously, I was going to say the Sauron’s full plate armor set (including helmet) from LoTR.
As a runner up, the Book of G’Quan from Babylon 5, it’ll take up a lot less space.
The knife from “That’s not a knife. This is a knife.”
Pulp Fiction, whats’in that brief case?!
https://www.digitec.ch/en/page/the-legendary-pulp-fiction-briefcase-what-was-in-it-15601
With scorch marks…
BTW, I’d love to have a lightsaber, but only if the blade actually worked (laser/plasma/energy that somehow ends three feet from the hilt).
I’m afraid all we earthlings would get is light-up plastic…
20 inches tall!
Unrealistically it would be cool to have the Electric Mayhem’s bus from The Muppet Movie. Especially if it was drive-able. But that actual prop is long gone - even Disney couldn’t find it (and would a 1966 bus be drive-able today?)
Realistically how about the signed copy of Tom Sawyer from It’s A Wonderful Life?
In Creepshow (1982), there is a jade-green ashtray used in all the stories (in the first one, it was a murder weapon). I don’t smoke, but it would make a good conversation piece.
Adam Savage made a replica.
The town model from Beetlejuice - but I’d have to put it in the basement because we don’t have a big attic.
Some of the gadgets from Star Trek would be fun to own. I was once on a tour of the actual set of the bridge of the “Enterprise” and held in my hand some of the gadgetry – the communicator, tricorder, and phaser, for example. They looked like the pinnacle of super-advanced technology on TV, but I was surprised at how crude they looked close up. They were only good enough to look good on TV. Close up they looked almost like cardboard mock-ups, but would still be pretty cool to have while watching ST:TOS!
On second thought, to hell with this small level of thinking – I want the whole bridge of the Enterprise relocated to my basement! 
I have a copy of the Maltese Falcon, bought from New York’s Mysterious Bookshop forty odd year ago. One of the most pleasing things about owning it has been the regularity with which people ask, “What is it made of?”
“The stuff that dreams are made of.”
Is that how you got your user name?
Beat me to it! That’s the perfect answer for the Maltese Falcon.