Personally, I found Zunes software to be excellent. I have actually grown to really love it, and it is by far my favorite Music player now.
I have a rather large music library, and I just find it easier to sort in the Genre view etc.
Its also quite easy searching. It looks nice, has wallpaper of the artist thats playing.
For instance, in fullscreen mode if you are listenting to the Eagles Hotel California, there will be pictures/wallpaper of the Eagles.
Lets say Lynyrd Skynyrd comes up next. .. same thing for them.
Nice little touch.
Its also capable of managing and organizing Videos,Pictures, and Podcasts, which is actually pretty good for Seasons of shows.
Just takes a bit of work to get it all tagged and your sorting preference set.
Zune can do a Mix of whatever music you want. If you choose this option, it will just play a mix of everything thats similiar to the 1st song you choose.
The software is free, and can be used freely as well. However, for a fee, It gets even better with a Zune Pass.
With Zune Pass, youll get unlimited access to music. Dont have it? Download it & listen to it all you want.
It also looks in the market place to add music for its MixView, if you have a subscription & want it to. Otherwise just your library.
By default, Zune uses your Windows 7 librarys to add contents. However, you can change this having it ignore them, and manually assign what folders you want it to look in.