Battle Royale: The Golden Age of Guitar Harmonies

I was listening to the "Cowboy Song" by Thin Lizzy yesterday and got to thinking about twin-guitar harmonies. It seemed like every hard rockin’ arena band from the '70s had them, and then, sometime in the early '80s, they abruptly fell out of favor, possibly due to Boston’s egregious overuse of the technique.

What I’m looking for is the best example of the technique.

To be clear, I’m not looking for the longest solo employing guitar harmonies or the most intricate. I’m looking for the one that most captures the spirit '70s arena rock in all its bloated glory. My determination as to who has the belt will be both arbitrary and capricious. In the event that I can’t decide if an entry is the current winner, the matter will be decided by the first two people to vote in favor of, or against, the entry.

Just to get things started, I’ll say the "Cowboy Song," but know that I have an Ace up my sleeve.