Recently i bought a nice collection of piano works of Stefan Askenase. Among other the box-set included a performance of Chopin's Nocturnes.
While hearing one of the Nocturnes, specifiacally No. 7, i realised that the WoW creators used part of it for a music piece you can hear mostly in Netherstorm and Hellfire Pennisula (yeah, i'm talking about burning crusade). I found the nocturne in YouTube, but sadly could not find the music from the game.