R&P.. what is your SINGLE favorite Heavy Metal song of ALL TIME?

Favorite metal song of all time? I'd have to say The Odyssey by Symphony X. Never have I heard such musical perfection in a song. I'd post a Youtube link, but the song's 24 minutes long, so it got divided up into three parts on Youtube, and you can't get the entire feel of the song by having to pause it to change to another part.