My all time greatest song would be a tie between "Tongue", "Sympathetic" and "Gasoline" (all by Seether).
I couldn't even pick a favorite album, but here's ten songs from off the top of my head.
Nothing Man - Pearl Jam
Relive the Magic... Bring the Magic Home - Reggie and the Full Effect
Nightingale - Saves the Day
Hands Down - Dashboard Confessional
Exit, Emergency - Houston Calls
Paris in Flames - Thursday
Sheena is a Punk Rocker - The Ramones
I Want to be a Homosexual - Screeching Weasel
Kill the Poor - Dead Kennedys
These Days - Nico