PowerBook G4

The PowerBook G4 debuted in 2001 with a titanium shell that made it the thinnest laptop on the market at the time, a genuine head-turner next to the plastic laptops most of the industry was still shipping.

Apple switched to an aluminum enclosure in 2003, offering the design in 12, 15, and 17-inch sizes and setting the aesthetic template — unibody-style metal, minimal ornamentation — that the MacBook Pro would carry forward almost unchanged for the next decade.