Tom Lehrer - LY (from The Electric Company TV show)
http://www.youtube.com/watch?v=x-jEMrBBDv8
T.L. was (he's not dead but still: was) a songwriter and satirist starting in the 50's when he quit lecturing math. Story goes he quit being a satirist when Kissinger recieved the Nobel Peace Price, there was no way he could out-do that as a satire. In the 70's he wrote songs for The Electric Company, an educational TV show for kids. In this particular song, he shows us the importance of the letters L and Y.
EDIT: Some 70's and 80's stuff
Men At Work - Down Under
http://www.youtube.com/watch?v=GkWp19hbXrY
Doctor And The Medics - Spirit In The Sky (A group I have a hard time figuring out, either they're just about the worst of the 80's, or they're onto something. But anyway, the song itself is... well... bad)
http://www.youtube.com/watch?v=8jor2WblIVg
XTC - Making Plans For Nigel
http://www.youtube.com/watch?v=TVhNZGF65nU
Blondie - Denis
http://www.youtube.com/watch?v=s3WE0RiWvi0
Joan Jett & The Blackhearts - I Love Rock'n'Roll
http://www.youtube.com/watch?v=M3T_xeoGES8
Joan Jett & The Blackhearts - Cherry Bomb
http://www.youtube.com/watch?v=uW_HCdU-qEY
The Sweet - Ballroom Blitz (they started as a bubble gum band, but moved onto "harder" stuff soon. A weird but sometimes cool band)
http://www.youtube.com/watch?v=ZrBDivsSe3k
Slade - Run Run Away (another 80's hit)
http://www.youtube.com/watch?v=bHoPYLQvnQM
Then, some of the finest vocal work by
The Dubliners (w/Luke Kelly) - The Auld Triangle
http://www.youtube.com/watch?v=FqlnVbdLkos