1. Songbird is not by mozillia. if it was thent here would be no problem with it and it would be in theuniverse repositiory, but sadly there is a problem with the permissions I believe, so its not :( Bottom line is its not by Mozilla.
2. VLC-Plays any type of music or video, comes with a ton of options to keep you happy
3. For linux
-compiz-Desktop composer! Makes everything look nice, makes the cube effect, and makes transparancy work well
-Wine-Allows things from windows to work on Linux
-Wine Doors-Even better capability for things from windows, needs wine.
-amarok-loveah music players, very good for making playlists in two seconds.
-WICD-Best network manager out there that I can find.
-Openbox-Doesn't work with compiz, but its one lovey windows navigator. Try it out!
4. DropBox-Allows you to easily sycronize files between two computers. Its a life saver.