TubeLister - Generate a YouTube playlist from your opened tabs.
Playlist Hunt - Playlist Hunt is one of the best applications for Apple users to get the best music through it.
DiskyT - Youtube playlists done right
Book Playlist - Collaborative music playlists for your favorite books
OrganizeTube - Create video playlists from Youtube, Vimeo and other sources
Kobo Audiobooks - Experience the joy of being told a story