VLC media player
Simply the best multi-format media player
With so many mobile devices available nowadays, it's handy to have some way of syncing your data across them all.
doubleTwist is aimed at the media side of this issue, allowing you to synchronize the video and music across portable devices, including mobile phones, smartphones, PDAs, PSP, cameras, and MP3 players. It's ideal for syncing iTunes playlists across your mobile devices as well as many other media-syncing needs. That said, some users have reported problems syncing to certain devices so make sure that your firmware is fully updated before giving it a go.
The interface of doubleTwist is similar to iTunes, with a sidebar along the left-hand side to move between different categories. The main area displays the content of the device connected, although there's no support for drag-and-drop and few customization options.
You can play media within doubleTwist but perhaps most interestingly, you can even share content with other doubleTwist users that you've added to your Friends list. I also liked the fact that you can publish videos to YouTube directly from doubleTwist, although the uploading options are very limited.
If you're struggling to keep all of your audio visual data in sync, then doubleTwist is an elegant and user-friendly program with support for a wide variety of devices.