Land Raider Proteus. As an old school player I remember when Land Raiders only looked like the bad boy on the left and we didn't have the modern Land Raider sitting on every hobby store's shelf. Land Raiders used to be elusive things, things you heard about from veterans of the game, that as a young whippersnapper in the game you would never see.
Then the plastic Land Raider MK II kit came out and the Land Raider became as ubiquitous to space marines as a 3 plus save. I for one, remember when the Mark I was the Land Raider, and one of these days I am going pick up the new Resin version put out by the artists at Forgeworld, knowing that my sixteen year old self would have been pretty happy about it.
That and its a kick ass model.