i dont know enough about competitions to know what is the usual type of music...i do, however, know a lot about getting up in front of lots of people, and getting myself motivated (and my students "involved")
personally, i find its important to pick something FAMILIAR, yet "different"...something that makes YOU FEEL LIKE SPREADING YOUR PEACOCK FEATHERS, so to speak...something that makes you move as opposed to something you move to.....if that makes sense.....
it should be a song that gives the feeling of power, and confidence...a song that YOU OWN!!!

you got me thinking on this one...MUSIC IS SOOOOOOOOOO IMPORTANT!