In the most recent issue of Rolling Stone, the top 500 songs of all time were listed.  I can't do all 500 but I can show you the top 11.  What do you think?

11.  My Generation (The Who)
10.  What I'd Say (Ray Charles)
9.    Smells Like Teen Spirit (Nirvana)
8.    Hey Jude (The Beatles)
7.    Johnny B, Goode (Chuck Berry)
6.    Good Vibrations (The Beach Boys)
5.    Respect (Aretha Franklin)
4.    What's Going On (Marvin Gaye)
3.    Imagine (John Lennon)
2.    (I Can't Get No) Satisfaction (The Rolling Stones)
1.    Like a Rolling Stone (Bob Dylan)

I thought specifically the note about Imagine was very cool, since the Imagine Cup was named after the song Imagine.  Apparently, John Lennon woke up one morning in 1971 and sat at his piano and composed Imagine, "twenty-two lines of graceful, plain-spoken faith in the power of a world, united in imagination and purpose to repair and change itself."