I had also forgotten about the Helix.

But if I had to chose based on the thread title of coolness, I gotta go with the Moulton, a high-end model, if considered a folder; If I recall, it's unboltable in the middle of the truss. Even if no other reason, I consider the frame to be a work of art, and it would be in a position of view in a tastefully-decorated residence, fitting in well with my other industrial-modern pieces of furniture.