I'm slightly allergic to nickel so I have to give it up to titanium as the coolest metal. Even though it's been around for awhile, and there have been big advances in aluminum and magnesium and all their alloys, titanium still stands out. It has a nice look to the bare metal that gives it a softer appearance if that's the right term. Whenever I hear it, I think of space age materials, stealth jets, and race cars. It was supposed to be the material of today!!! What happened?!
I'm vey familiar with Titanium, I used to be an engineer with a company that made some of turbine blades for Rolls Royce jet engines with it, and I still have a ring I made for myself out of it.
I have a passing acquaintance as well, I've used it to make connecting rods in miniature engines. The strength/weight ratio allows the rod to be made lighter thus reducing vibration, there is no way to properly balance a one cylinder engine. It needs a bronze bushing to wear well, and machining requires a light cut, fairly high surface speed, and plenty of coolant.
My Leica II is made from Nickel and I think the metal on the lens is also of the same material. I find the finish/soft colour of the metal and its weight one of the most endearing properties of this camera. Were any other cameras manufactured from Nickel? I have heard some people have an allergy to this metal, so it may have a down side.
It should be clarified: cameras are made of an aluminium alloy casting, many parts of various materials such as steel, brass, plastic, etc; and are covered with brass covers which are either painted (usually black) or electroplated with either chrome , nickel, "black chrome" or, if you're an aspiring pimp, gold.
The metal you see when you look at the camera's top and bottom plates, (or a lens barrel), is an electroplated (or anodised) layer.