I've enjoyed kmp for a while as my default video player (recently freeze-free on my laptop!) and I have a couple of suggestions to improve your software:
How about a shuffle function for Playlist->Sort? This is especially helpful (compared to a regular shuffle through a arbitrarily sorted playlist) if you want to view all files in a random order, but ensure all files are played once before repeating any given file.
Also, "Always on top while playing" is an awesome function - is it possible to extend that to "Prevent screen saver" - so when video is paused, a screen saver still occurs?