I personally own a Zune 30, and I am very happy with it. I have never had an iPod, so I cannot speak to which is better, but I can say that a lot of the criticisms of the Zune are ill-founded.
Here you have an MP3 player with what I would consider to be a superior interface, same storage, bigger screen, integrated radio, and wireless sync, and it's about $100 less than the 30gb iPod... Easy decision.