Windows 8 Xbox Music and SmartGlass app updates available
Noticeable changes in the Xbox Music app are the return of SmartDJ, and a new Xbox Music Cloud Sync feature. There's new icons that seem to have to do with sync that are in the album info now too. And also settings for Sync in your options. I'm not exactly sure WHAT the Sync is syncing though, if it's including stuff that's not in the catalog, or what.
The SmartGlass update lets you control the 360 browser via your tablet now.
Update: Can't test SmartGlass right now because I have something else on the TV, but a few screenshots of Xbox Music so you can see the cloud sync options: