Right now, my favorite song is "The Lightning Strike" by Snow Patrol. They don't have the full song on Youtube, but you could listen to the 3 parts separately.
If you're looking for something a bit shorter (The Lightning Strike is over 16 minutes long), I'd say something like Sweet Disposition by The Temper Trap, or maybe Crusades by August Burns Red.
You see the world in black and white, No color, no light. You think you'll never get it right, But you might! Yes, you might!
Its a really good song, with great vocals and instrumentals. Its about logical and rational people, and how they need to feel more emotion and be more 'colorful'.
Mines changes every day depending on my mood. Yesterday it was front-line soldier by Bone Thugs and Harmony. Today it is The way i are by Timbaland because i've been watching step up.
I couldn't possible decide on what my favourite song ever was.