Jumpin' Jack Flash.

"Rock Around the Clock" really seemed to set the tone for the 50s rock era. "Johnny B Goode" strikes me more as an anthem for young musicians than the general youth populace -- look how many later songs have riffed on it ("Shooting Star," "Walk of Life," at least a couple more with young Johnnies rocking out). Neither really had much impact on the youth movement of the 60s, which had the British invasion as its soundtrack. "Satisfaction" and "My Generation" are good choices, but it really ought to be the Beatles, because they turned the whole rock thing around when it was dying in the early 60s. Most of their early songs like "I Want to Hold Your Hand" aren't very anthemic, but they certainly had that kind of impact. Alternately you could go for something reflecting the evolving social consciousness of the period like "Blowing in the Wind."

Is it too late to change my vote?

[youtube]http://www.youtube.com/watch?v=L6DSR9tZ1hA[/youtube]

a couple lesser know ones

The Modern lovers - Roadrunner
Velvet Underground - Rock 'n' Roll

But I'd have to go with Louie Louie, Johnny Be Good, Jumpin Jack Flash or Zep's Rock n Roll

For the first 20 years - Rock Around The Clock by Bill Haley & The Comets

For the next 20 - Long Live Rock by The Who

I dunno what it would be for the last 15 or so, there's been SOME decent rock, but has there been anything anthemic about Rock itself?

Hard Rock Hallelujah by Lordi?