See, this is why I heartily dislike IPod. You buy one and then spend loads of money on additional accessories and music. *sigh*
Anyway, if you were to get the Creative and were determined to use the Itunes there are two things you could do. I think the first was already mentioned...burn the itunes onto a cd, transfer them to your computer and theeen the Zen. Bit tedious, but it works. Otherwise, a mate of mine has this software called Tunebite and it converts and redoes the songs so they can play anywhere and they load quickly and easily on any player you get now or in the future. Also, there is shareware out there where your daughter can load music and movies for free (not competely legal, but honestly people..how else can you get obscure independent imported tracks, etc)such as Limewire (limewire.com v.good) and Bearshare (bearshare.com). And you daughter sounds like a bit of the rebel so she might enjoy accessing these and everything is in basic mp3 format and should work with any player she receives.
I hope this all helps and good luck!