That's a great wallpaper.
A while back I used these Believe In Blue wallpapers that I found when I was bored and was searching for Canuck wallpapers :
...but now I just have a pic of me and my siblings when we were really little.
Love those. I don't think I can choose a favourite song. I really like their new one called United States of Eurasia, and I've been listening to Map of the Problematique a LOT lately...I don't have a favourite though, they're all great.