Antonio Banderas performed (along with Carlos Santana) the theme song from The Motorcycle Diaries (2004) instead of singer/composer Jorge Drexler who performed in the movie but wasn't chosen by the Academy for the live show because he wasn't famous. Drexler eventually won the Oscar and instead of making a speech thanking everybody, he just kept singing the chorus of the song in the way it was supposed to be performed.
Each of the 5 Best Picture nominees share a common themes of ambition and success: Million Dollar Baby (2004) (Maggie and boxing); The Aviator (2004) (Howard Hughes and film-making/engineering); Finding Neverland (2004) (J.M. Barrie and writing); Ray (2004) (Ray Charles and music). Sideways (2004) (Miles & Jack and resolving a mid-life crisis)