One of my favorite movies is The Royal Tenenbaums. The ending is great. Even though the movie ends with a death, it's still sort of a celebration of life and looking ahead. Van Morrison's Everyone, which plays as the film ends, pretty much embodies that feeling. It's a perfect fit and it's difficult to think of another song that would be better in this situation, just because that scene is so ingrained in my brain. It's also a little testament to director Wes Anderson, who picks some really great and fitting songs for his soundtracks. You may or may not like his movies, but his soundtracks are stellar. Despite the song appearing in the film, it's not on this soundtrack. However, you can go straight to the source and find this song on Morrison's classic album, Moondance. Check it out.
Van Morrison > Everyone