If you have a new MP3 player that needs to be used in MTP mode for advanced features like playlists and sync to work, then Windows Media Player does the job fine but there are problems with Linux. I found that the Sony MP3 players, the famous Walkman series never gets detected as an MTP device, and none of the common media players (Rhythmbox, Amarok, Banshee) can write playlists to the device in the required (*.pla) format. Luckily there is a solution to this problem...