Of the cameras I have owned, the Mamiya Universal Press with the 100/2.8 was the coolest. I mean 120, 220, and Polaroid. And on that Polaroid, think of it, a Polaroid with a 100mm f/2.8 lens that was sharp from corner to corner! It seemed to draw the most attention of anything I regularly used.
Of the cameras I currently have, I think the Iskra is the coolest. Proof that our government lied to us when they said that the Russians could not make great stuff. It seems to have the sharpest Tessar pattern lenses of anything I have seen, even web sized scans look incredible.
I think the Hapo 66e (rebranded Balda Baldix RF) gets the most comments. Usually of the "Nice camera!" sort, so I guess it wins "Coolest to non-photographers". Or maybe it is because it is obviously an old camera that looks pretty much like new. It is also my favorite pocket camera (it's a 6x6 folding 120 camera). I only wish it had a more sophisticated shutter on it. Some day I might find a nice clean Baldax (coupled RF version) that I can afford.
Another folder that I rate as way-cool is the Kodak Duo-620, I have not gotten around to re-spooling film for it, so I have not actually used it yet. What I find fascinating is that Amelia Earhart supposedly carried one like it on her ill fated round the world flight.