When I play audio files in VLC, I like to have the equalizer and playlist open, and these are separate windows from the main VLC window. I can see how this is useful to many people, but I would personally prefer to have the playlist and equalizer in the main VLC window, as tabs like a browser has. I don't know if this has been suggested (a quick search for "tabs" didn't pull up anything that looked relevant), but I think it would be a desirable feature. It would also be nice if VLC could be set to remember which tabs were opened before and in what order, and had the option of restoring this layout the next time it runs.
Thanks for the best media player ever made, btw.
Edit: Just found an option to dock the playlist, so I am aware of this feature now, but it's not the same.