Futura. The very name brings to mind jet-age splendor of the highest order, and indeed the text on the commemorative plaque left behind on the Moon by the Apollo 11 astronauts in July, 1969 is set in Futura. There is no other font that can do what it does with the same impact. You might say Futura is to Helvetica as driving a Porsche is to driving a Toyota--they both get you there, but the former does it with so much more fun.
Futura was designed by type design luminary Paul Renner