People who should be more famous than they are

[gumpzilla]

John Bardeen. Physicists (and probably a lot of EEs) would know him, but he's the only guy to have won two Nobel prizes in physics, and one of those was for the transistor, which seems like an easy winner for "most practical thing to come from quantum mechanics so far," and yet is quite unknown as far as really awesome scientists go. There's a biography of him out there, which I should read sometime soon. (EDIT: The other Nobel was for his work on the BCS theory of superconductivity.)