I've had the 30gb Zune when it came out, sold it and bought the 80gb the month it came out. Couldn't be happier. There is a registry hack where you don't have to use the software @ all, however the newest updated software is pretty decent (the version before sucked ass). I listen to mostly obscure bands and most of the shit I want is on their marketplace, however one draw back is that some albums are on there for a limited time and you'll lose your music. Lost my whole Government Issue discography. There is a nice feature about the subscription though, every month you get 10 free songs of your choice to keep for good.
The wi-fi is where its at though. You can sync your zune wirelessly as long as its plugged into a power source. I keep my zune hooked to the surround sound in the living room and my laptop is in the bedroom, everything just syncs up periodically. Also if you are sitting at McDonald's and feel like hearing a song, you can connect to the marketplace from your device (no laptop necessary) from any Wireless network and listen to whatever you want just like your own custom radio station.
Another cool feature is that when listening to the FM tuner and the radio station has a digital code (tells you what songs are playing) if you hear a song you like, you can queue the song and download it later when you sync up to your home PC.
If you have an Xbox 360 connected to the wireless network, you also have your WHOLE music library at your disposal including playlist. You can have all your music on your PC and never have to fill up your Xbox HDD space.
Sharing is kind of a cool feature when you are away from any wireless network and your buddy has a few songs you wanna hear BAD. Sucks they only last for 3 days though.