I love Zune software - it is so much better than iTunes. But actually to use and synchronize your Windows Phone 7 you don't really need Zune at all.
This one area where it suddenly asked me to connect to Zune was to grab Podcasts. Personally I kind of wished that the phone would just synchronize without connecting to a computer, but on the other hand, if you had lots of music on your computer or network, you'll need Zune to get it synchronized onto the phone.
Zune is just pretty, and detects all the iTunes library effortlessly.