Better sounding music - even though the Zune does not have an equalizer people have reported that the music sounds better.
Can use click and/or touch - if you don't like the click wheel (from the iPod) you are able to use the touch method on the Zune where, for instance, to go down a list you just touch the bottom of the pad.
Great screen - large, clear and easy to read.
Navigation - once you are used to it, it is very friendly.
FM radio - also includes RDBS
Supports podcasts - so you can still get you fix of your favorite podcast
Wireless sync with PC using WiFi - so much better than a cable!
Well made - feels solid.
Battery life - a common complaint for media players, especially for people who watch a lot of video.
PC Software - the software can take a while to get used to (so much so, people can give up), but once you're used to it, it's better than iTunes.
Changing from an iPod - Apple doesn't make it easy to move music!
Cannot be used to store files - this is a feature most MP3 players have, strange that the Zune doesn't.
Overall the Zune is a welcome addition to the media player market. It can be hard to give up your iPod, especially when you are used to it, but you should consider the Zune next time you are looking to replace your media player.