On the heels of "when did rock die", I went dumpster diving for this thread.
some of my personal favorites:
Money- Pink Floyd. One of the first solos I wanted to learn how to play on guitar.
Just what I Needed- The Cars. Short, but brilliant.
My Sharona- The Knack. Still blows me away.
Stairway to Heaven- Led Zeppelin. Timeless and classic.