Ubuntu has for a while now (and this is still to be found in the latest Karmic Koala release) included an extremely nifty and helpful little built in preview tool that is aimed squarely at music files like the classic MP3 format for example.
And to see it in action is pretty easy.
Simply browse to any folder that contains some music files. Hover your mouse of any file that has been identified as an MP3 file and wait a split second or two – you’ll notice that the file icon will now be overlaid with a small music note in a speech bubble. Pretty soon you’ll hear you speakers spring to life and the MP3 that you are hovering over will be playing over them.
Now that’s nifty, right? Hopefully the next thing they manage to do is provide for movie file previews in the same manner – now that would be even more awesome! :)