Is there a way to set the media library to automatically watch a folder for new content? Kind of like "watched folder" in winamp.

Alternatively..

Is there a way when adding files to a playlist, only add files not already there (and rescan changed files)?

there are some plugins for this, for example:

Playlist Bind (foo_playlist_bind) - Synchronize playlist with contents of specific directory.

it seems it will have to rebind everything, and locks the fb2k gui while doing so

thanks though!