I pretty much always have my mp3 set on shuffle, so fate gets to decide that. Just to clarify, my music taste is vary wide, so it could end up going from Ozzy Osbourne, to some of Beethoven's symphonies, to Maroon 5, to AC/DC, to some J-Pop, to video game music remixes, etc., etc. Shuffling the music actually works as a stimulant, as since I don't know what out of a large selection of genres to choose from, it keeps my mind from becoming complacent with the same type of music for long periods of time.