I would totally choose the late 60s and early 70s for a few key reasons:
1. The fashion was so crazy and so rad!
2. The music. There was Motown going on along side the Beatles, Elton John, Lynyrd Skynyrd, the Kinks, Simon and Garfunkel, Led Zeppelin, Elvis Presley, etc. etc. Oh and Woodstock. Man, it would've been great to be alive.
3. Paul Newman in his acting prime. Cool Hand Luke in '67, Butch Cassidy and the Sundance Kid in '69, The Sting in '73. Movies aren't like they used to be. If you're also feeling nostalgic for an era you never lived in, let me know. Oh and check out The Long, Hot Summer, my most favorite of Paul Newman movies (made in the 50s, not 60s though).