Cliche, but Sabotage was always my favorite.
[ame=http://www.youtube.com/watch?v=z5rRZdiu1UE&ob=av2e]Beastie Boys - Sabotage - YouTube[/ame]
Sorry if this has already been posted, but here's a pretty cool tribute from Coldplay to the Bboys after MCA passed....
RIP MCA - YouTube
I'm not a huge Coldplay fan, but that's a pretty cool gesture on their part.
Paul's Boutique is a fantastic album, and really launched them into what they became: One of the most popular eclectic bands ever.