Continuing with the "Pony Themes" project here comes Twilight's theme
Twilight's sonata, upbeat, slightly dark and overall magic

Music composed by Derpy Hooves (WherewolfTherepony)
Album Artwork by Grey Nightmare

Project info here: http://www.everypony.com/forums/showthread.php?74-Derp-Song-for-a-Pony

Download link here:
http://soundcloud.com/wherewolf-therewolf/twilights-sonata