I think you're slightly too pessimistic about the public imagination and the standing of the professor in the US. Some other examples off the top of my head (and Linda's -- it's a good dinner-table game):

Stephen Hawking
Richard Dawkins
Stephen J. Gould
Carl Sagan
Henry Louis Gates
Carol Gilligan

If we go back a generation, we might add Mortimer Adler, Buckminster Fuller, Marshall McLuhan, and Benjamin Spock. I'm sure I'm missing some obvious and importance additions.

Telling that with the exception of Gates (who is famous partly because he's perceived as controversial--you could add Cornell West to the list as well), they're all scientists. There was a book a while back about the scientist as the new public intellectual, wasn't there?

Pausch, of course, was a scientist too, but that wasn't what captured the public's imagination.