The Eagles song Life in the Fast Lane written by Don Henly is widely rumored to be about Stevie Nicks and Lindsey Buckingham of Fleetwood Mac. Supposedly it is Henley’s observations of their relationship. Stevie is “terminally pretty” and Buckingham is the “hard-headed man”.
Likewise the Henley-penned Eagles song Victim of Love is about the love triangle between Henley/Nicks/Buckingham once Henley got involved with Stevie.
If I may add to my OP:
Dear Prudence by the Beatles is written for Mia Farrow’s sister, Prudence. She was part of the Maharishi Mahesh Yogi visit in India, and stayed in her room a lot: hence “Won’t you come out to play?”
Stevie Nicks’ “Edge of Seventeen” was written after a night out with Tom Petty and his wife. Petty’s wife is from Texas, and at one point in the conversation she talked about something that happened when she was at the “age of seventeen”. It sounded like “edge” in her Texas accent, and it inspired Nicks to write the song (and have Tom Petty sing background).
I heard that on the radio some time back–hope I have the facts straight.
Well, since my "Waterloo Sunset" story was debunked, I’ll try another…
"Who Are You" is about a night when Townshend was partying with members of The Sex Pistols. He got plastered, gave them a drunken lecture, and ended up passing out on the sidewalk. The local constable recognized Pete and decided not to arrest him. The “eleven hours in the tin pan” alludes to a marathon meeting with Allan Klein.
Oh, by the way, it was Roger’s idea to add the expletive to the chorus.
Another piece of Who trivia. Roger Daltrey’s stutter in “My Generation” is a drug reference. The Mods, who were Who fans, used amphetamines as their recreational drug of choice. And one of the signs of amphetamine abuse is stuttering.
Randy Bachman’s stutter in “You Ain’t Seen Nothing Yet” was more personal. He did it to mimic his brother Gary who stuttered.
“Mother and Child Reunion” was the name a Chinese dish but the lyrics were inspired by the death of his dog. “I can’t for the life of me remember a sadder day.”
I wonder what other songs pop songs are about pets?
(from wikipedia)
The Don Henley Stevie Nicks relationship does have one immortal song directly associated with it, Stevie Nicks’ Leather and Lace.
Stevie was writing the song on commission from Waylon Jennings as a title song for his forthcoming album, Leather and Lace, to consist of duets with wife Jessi Colter. Stevie struggled mightily in creating the song, with Henley’s moral support and constant encouragement. When this gem of a song was finally ready, Waylon and Jessi happened to be breaking up and the Good Ol’ Boy was intending to sing it by himself.
Not all right with Stevie. As she completed its writing she was coming into the middle portion, timewise, of a romantic relationship with Don. The song, of course, was about them, and in any case is unimaginable sung any style other than duet.
Waylon and Jessi’s album of duets, Leather and Lace, was released without this song. Stevie and Don recorded it together and it was released on Stevie’s 1981 debut album as a solo artist, Bella Donna, which went Platinum in 3 months.
I thought it was well known that it’s about Mick Jagger. She mentioned it in an interview back when the song first came out.
John Lydon, aka Johnny Rotten, auditioned for The Sex Pistols with Alice Cooper’s “Eighteen.” Further, the song “Desparado” was in honor of Alice’s friendship with drinking buddy Jim Morrison.
And Alice’s “House Of Fire” was co-written by Joan Jett. Oh, and Jon Bon Jovi sings on Trash, both on the Trash album.
Hey, it’s my fellow obsessed Alice-ee! 
She has denied it was Jagger. On her website, she has posted her interview with the Washington Post in 1983:
**
WP: Who was ‘You’re So Vain’ about? Mick Jagger?
Carly: No.**
And on Sunday Morning with Rita braver in 2001:
**
Rita Braver: Everyone thinks ‘You’re So Vain’ is about Mick Jagger.
Carly: Oh, they don’t really think that.
RB: Yes - they do.
Carly: Okay.
RB: Is it?
Carly: Oh, no, no, no.**
Aerosmith’s “Dude Looks Like A Lady” was inspired by the members of Mötley Crüe. In his book “Walk This Way,” Steven Tyler writes
“Then one day we met Mötley Crüe, and they’re all going, ‘Dude!’ Dude this and Dude that, everything was Dude. ‘Dude (Looks Like a Lady)’ came out of that session.”
Nikki Sixx, in his book The Heroin Diaries, has said that the song was specifically about Vince Neil.
It’s about me, isn’t it?
She told Howard Stern (off air). I think a handful of people have been told.
Wouldn’t it be three? Can’t it be assumed that, by now, the person to whom it refers knows that it’s about him? And, if she did tell Howard Stern, that’s 4 plus.
This is turning into that Monty Python sketch about the Spanish inquisition.
And I don’t think anybody expected the Spanish Inquisition in a pop song trivia thread. 
I had always heard it was about Warren Beatty, but I don’t have much faith in that.
RR
Singer Murray Head is the brother of Buffy’s Anthony Stewart Head.
Murray was the only singer who forgoed getting paid $250 for singing on the original Jesus Christ Superstar album in exchanged for 1/2 of 1% of the royalties. It made him a millionaire.