When I was about 10 I got a View-Master for Christmas. It was beige plastic and came with a few Loony Tune reels. I thought it was ace; 3D Daffy Duck in space. A little while later my Mom came home from a jumble sale* with a battered leather case and inside were two vintage View-Masters, along with a whole pile of old reels.
Now this was something else entirely. To be honest, it took a while for it to dawn on me that these were much more interesting. One View-Master was made of steel with a black enamel finish, a Model C, the other was a brown bakelite Model E.
The reels showed me the world in all it's 3D glory: lots of US landmarks and cities, European capitals, fiords of Switzerland, even pictures of the Queen's Coronation. The age of the slides giving all these places an odd yellow tinge.
As an adult, I found this Model C complete with it's original box and insert leaflet. A little digging around and you can find all you would ever want to know about them here including a really great image library of original packaging.
* Indication of the origins of Ace Jet.
See also the Typepad View-Master.