i know nothing about the Zune.
but i've owned both a 30GB Ipod Video and, currently, a 160GB Ipod Classic, and i've not had problems with either.
i really like the interface, and media players are pretty much guaranteed to support the Ipod since it's so popular.
plus, it's the biggest HDD mp3 player on the market right now.
however, i would recommend using winamp or foobar for synching and managing your library, as itunes is fucking slow as fuck, and takes up a massive amount of computer resources to run.
also, my battery life is remarkable. i went almost an entire week without charging it, while listening to it almost non-stop. of course, i had the brightness waaaay down and the backlight set to 2 seconds, but even set normally, it can go in the range of 20-25 hours without a charge, easy.