"Ten Years Gone" (Led Zeppelin)

If you've never read Cameron Crowe's 1975 Rolling Stone article "The Durable Led Zeppelin," read it.  It sheds light on a number of things about the band--namely, what's fact and what's fiction.  It also confirms that they're intelligent, talented guys who were intensely serious about their music (even when they weren't being all that serious on the road).  It's really a great, well-written article by an 18-year-old Crowe.
In the article, lead singer Robert Plant reveals what the song "Ten Years Gone" from 1975's Physical Graffiti is all about:

"Let me tell you a little story behind the song 'Ten Years Gone' on our new album. I was working my ass off before joining Zeppelin. A lady I really dearly loved said, 'Right. It's me or your fans.' Not that I had fans, but I said, 'I can't stop, I've got to keep going.' She's quite content these days, I imagine. She's got a washing machine that works by itself and a little sports-car. We wouldn't have anything to say anymore. I could probably relate to her, but she couldn't relate to me. I'd be smiling too much. Ten years gone, I'm afraid."

Various articles I've read over the years have said that the woman he's singing to/about in "Ten Years Gone" is Shirley Wilson, the sister of Plant's then-wife Maureen Wilson.  Shirley, Plant's girlfriend from the mid-60s when his career was just getting started, wasn't a fan of the rock & roll lifestyle, and she gave Plant an ultimatum.  So they split up, and Plant took up with her sister, Maureen, who was less concerned about his constant gigging and all of the trappings of life on the road.  
Despite building a life and having three children with Maureen, Plant pined for Shirley (as is crystal clear in the song).  Some years later, after he and Maureen had divorced and Led Zeppelin had disbanded, he and Shirley got back together for the better part of a decade and had a son, Jesse Lee, in 1991.
While the history behind the song is bar-trivia interesting, it's the quintessential Zep treatment of this ballad that draws me in every time.  The shifting dynamics, the thunderous rhythm section, Jimmy Page's crunching riffs and countless layers of guitars (especially on that gorgeous bridge), and Plant's expressive vocal--they all combine to create an intensely powerful, yet immensely tender, song.  I don't know of many bands that could pull that off without sounding hokey.