Although I like internet radio, and have a number of subscribed stations in my Library, I would often like to listen to my local music files without getting into a neverending internet stream. Rather than unchecking all radio stations manually, it is possible to use a Smart Playlist to do the work for you. There are two ways to this, at least. Create a new smart playlist with either of these criteria:

1. Limit by Kind -- does not contain -- stream
2. Limit by Kind -- ends with (or contains) -- file

Either of those will result in a Smart Playlist containing only your music, and no internet radio stations.