i generally find that when im on mdma, all music sounds better, but generally the music which you normally like will sound the best. obviously, i think peaking gives you a greater appreciation to dance music like (eg trance) imparticular, but i would still recommend just having lots of whatever music you normally like.
otherwise, if you like tiesto, try get you hands on some of his cd`s, or alternatively get some paul van dyk, armin van buuren, blank &jones etc, all play melodic/uplifting trance. if you wonna get the party pumping try some harder stuff like dumonde, dj scot project, cosmic gate etc. let me know if you want some more specific tracks though, or you can just browse some of the threads in the music forums on trance.
generally though my advice would be not to worry too much about preparing everytihng beforehand. it will be good to have some things ready, but dont have your night set and planned before it even begins. just relax and let it all progress as it does normally, and believe me you`ll haver a good time.