After the Gold Rush by Neil Young.
Wooden Ships by CSN&Y.
1984 - David Bowie 
and for a post-apocalyptic future,
(Nothing But) Flowers - Talking Heads
and then, not a song about the future, but a video set in a post-apocalyptic future,
You Got Lucky - Tom Petty and the Heartbreakers
“What in the World??..” by the Dukes of Stratosphear
Queen - '39
The Future Soon, by Jonathan Coulton
’39 - Queen
Pretty much the entire Diamond Dogs album by David Bowie. The entire thing is set in a future that’s not exactly post-apocalypse, but post-collapse (maybe just post '70s), combining Orwell’s Oceania with the residual decadence of the glam period.
Especially since the line about the guy having an affair with a random computer is one of the more accurate predictions I’ve heard.
Jefferson Airplane had a bunch of songs (not good) about stealing a starship, right out of Heinlein. And if you consider after the war songs to be about the future, Dylans “A Hard Rain Is a Gonna Fall” and “Talking World War III Blues” are definite candidates. The latter song takes just about every WW III cliche, chews it up and spits it out in one verse.
“I lit a cigarette on a parking meter and went on down the road
Just a normal day.”
“Faith of the Heart,” Rod Stewart.
What?
“Living in the Future” by John Prine
We are living in the future
I’ll tell you how I know
I read it in the paper
Fifteen years ago
We’re all riding rocket ships
And talking with our minds
And wearing turquoise jewelry
And standing in soup lines
We’re standing in soup lines…
Of course, as Prine says, he wanted to write a song about the future, but it took him 15 years to write it, so at best it’s about the present.
I was dreamin’ when I wrote this, forgive me if it goes astray
But when I woke up this mornin’, could’ve sworn it was Judgment Day
The sky was all purple, there were people runnin’ everywhere
Tryin’ 2 run from the destruction, U know I didn’t even care
Cuz they say 2000 zero zero party over, oops, out of time!
So 2night I’m gonna party like it’s 1999!
Prince, 1999
Can we start this thread over so I can be the first one to mention this? I freakin love this song, one of my very favorite songs by one of my very favorite bands.
Blows Against the Empire was technically the first Jefferson Starship album, although it was really a vanity project by Paul Kanter. It’s pretty much the same mindset that was first shown on “Wooden Ships,” simultaneously released by Jefferson Airplane on the *Volunteers * album and Crosby, Stills, and Nash on their first album.
Just to show you what the times were like, Blows Against the Empire got a Hugo nomination for Best Dramatic Presentation. (It lost to “no award.”)
Does anybody else wonder if the title was an inspiration for a certain California filmmaker who turning his student film into the dystopian future world of THX 1138 at about the same time?
The Steve Miller Band, “(I’m A) Space Cowboy”. Bet you weren’t ready for that.
R.E.M., “It’s The End Of The World As We Know It”. And I feel fine.
Sugar Ray, “Someday”. I’ll look around, and wonder why you were always there for me.
When I’m 64 - The Beatles
Oh yeah, and how many people now 35+ years old used to think that the events depicted in Nena’s 1984 hit song “99 Luftballons” (a.k.a. “99 Red Balloons”) was sooner or later going to come to pass?
Mann, wer haette das gedacht
Dass es einmal soweit kommt
Wegen 99 Luftballons?
This is what we’ve waited for,
This is it boys, this is war!
The president is on the line,
As 99 red balloons go by…
Technically about the present, and how it isn’t the future we imagined, but
“(It’s the Eighties, So Where’s Our) Rocket Packs” by Daniel Amos:
The Future’s So Bright I Gotta Wear Shades - Timbuk3
The sun’ll come out TOMORROW…
probably fairly obscure, but how about Beyond Tomorrow by Stan Ridgeway?