BitPlayer

I prefer VLC (as I think another reader has mentioned): http://www.videolan.org/vlc/ It works like a charm for almost any video file you can imagine, and it's opensource and free and slim. (The only trouble I've ever had trouble with, oddly, is playing actual DVDs from VLC, but DVD player rocks the mic for that one).

Isn't it wierd how Quicktime doesn't support fullscreen but iTunes does?

For users who don't need to export into different media type, I think VLC http://www.videolan.org/vlc/ is a much better option. It too has playlist, but can play just about any video file you throw at it.

I found this little gem over a year ago and put it to use in our university TV studio. It feeds "slides" and video for journalism classes. Some of the users were reluctant at first. Now everyone raves about it. I looked at a lot of "playlist" apps, and BitPlayer is simply the best. It can handle stills, movies, Flash, animated GIFs -- all the usual QuickTime stuff. The playlist truly works as a playlist, instead of an unstoppable "slide show" as with many other apps. Since the computer is not a full-blown editing station, we capture video with BTV Pro. If there is any excess video at the beginning of the capture, BitPlayer features IN and OUT point markers. If you want a very simple alternative to Keynote (or Powerpoint), give BitPlayer a try.