Marvel Comics, 1982
If you're looking for some design inspiration, check out the new and mostly older letterheads over at Letterheady. My favorites are the ones from the animation studios but you'll find interesting letterheads by everyone from Albert Einstein to Adolf Hitler.
M. J. Winkler, 1925
Walt Disney Productions, 1938
Walt Disney Productions, 1951
You can also submit any letterheads if you think they deserve some much needed attention.