I don't know about The Velvet Underground being rock, as such - although if they are, just about anything by them...
Otherwise I'd go for any really good Neil Young wig-out (the fifteen-minute-plus version of Like a Hurricane, with interminable break-downs and build-ups, that I saw him do live remains one of my favourite gig moments ever.)
50's: Singing the Blues (Tommy Steele version - I have the 78!)
60's: With a Girl Like You - The Troggs.
We have all been there.
Gone to a dance, seen a beautiful girl, stare at her all night,
never get the courage to ask her for a dance. Go home alone....
"To you, across the floor my love I'll send."
Brilliant. Best lyrics of the 60's.
70's: Anarchy in the UK/God Save the Queen - The Pistols.
Every decade after that produced bland crap.