Since we've all established in another thread that singles rule the naughts and that this decade lacks a decade-defining album, I'm going to make one. This is my "greatest hits" of the 2000s, the songs that defined the decade, fully formed into one cohesive album (as best as possible):
1. OutKast - "Hey Ya"
2. 50 Cent - "In da Club"
3. Eminem - "Lose Yourself"
4. Gnarls Barkley - "Crazy"
5. Coldplay - "Viva la Vida"
6. Kanye West - "Stronger"
7. The White Stripes - "Seven Nation Army"
8. M.I.A. - "Paper Planes"
9. Journey - "Don't Stop Believing"
10. Daft Punk - "One More Time"
The song made an enormous comeback this decade, and it's probably one of the top viral songs ever. It's #1 in iTunes downloads for non-2000s songs, and it's been used in, among others, The Sopranos, Glee, Rock Band, baseball games, and I would say it's probably the most popular "old" song among today's young'uns. Though this maybe strictly an American thing, I really don't know.