Here's 50 in alphabetical order by artist. This is a pretty tough exercise. I'm sure I left out a lot of stuff. I didn't include a lot of 2000s stuff, simply because I haven't lived with most of it enough to say it's an "all time favorite".
I will say that these are 50 pretty sweet songs:
Afghan Whigs - ”Debonair”
Beastie Boys - ”So What'cha Want“
Bob Dylan - ”Girl From The North Country”
Camper Van Beethoven -”Take The Skinheads Bowling”
Cheap Trick - ”I Want You To Want Me”
David Bowie -”Ziggy Stardust”
Donovan - ”Hurdy Gurdy Man”
Echo & The Bunnymen - ”The Killing Moon”
Elliot Smith - ”Needle in the Hay”
Guided By Voices - ”Game Of Pricks”
House of Pain - ”Jump Around”
INXS - ”Don't Change”
James - ”Laid”
Jesus and Mary Chain -”Head On”
Johnny Cash -”Folsom Prison Blues”
Lou Reed - ”Walk on the Wild Side”
Marvin Gaye - ”Let's Get It On”
Modern English - ”I Melt With You”
Modest Mouse -”3rd Planet”
Morphine -”Candy”
Pink Floyd -”Mother”
Pixies - ”Where Is My Mind?”
Prince - ”Purple Rain”
Queen and David Bowie - ”Under Pressure”
R.E.M. - ”Country Feedback”
Radiohead -”Creep”
Social Distortion - ”Ball and Chain”
Sonic Youth -”Teen Age Riot”
Talking Heads - ”Wild Wild Life”
The Beatles - ”Sexy Sadie”
The Cars - ”Just What I Needed”
The Church - ”Under The Milky Way”
The Clash - ”Train In Vain”
The Cult - ”She Sells Sanctuary”
The Cure - ”Boys Don't Cry”
The English Beat - ”Save It For Later”
The Outfield - ”Your Love”
The Ramones - ”Blitzkrieg Bop”
The Rolling Stones - ”Sympathy For The Devil”
The Smiths - ”How Soon Is Now?”
The Stooges - ”Search and Destroy”
The Who - ”The Seeker”
Tom Waits - ”Jockey Full of Bourbon”
TV on the Radio - ”Wolf Like Me”
U2 - ”The Fly”
Velvet Underground - ”Sweet Jane”
Violent Femmes - ”Add It Up”
White Stripes - ”Fell in Love With A Girl”
XTC - ”Dear God”
Yeah Yeah Yeahs - ”Maps”
-----
People claim I'm possessed by the devil, but mama, I know I'm possessed by your daughter.