MPlayer lacks a playlist though, which is annoying.
VLC's recent UI changes have been a step backward (specifically making it impossible to see the playlist and the video at the same time), but at least you can queue things up to play.
MPlayer OSX Extended[1] is your friend. It has playlist, it has nice interface and you could swap out MPlayer player binary with a newer one (e.g. mplayer2-git[2] or build your own via Homebrew[3]). I like MPlayer OSX Extended far more than MPlayerX or any other alternatives, shame that it didn't get the attention it deserves.
Actually, VLC can still display a separate playlist and playback window. You just need to uncheck "Show video within the main window" in the Preferences. http://feepk.net/customizing-vlc-for-mac has some other tips for making things look more like they do in 1.x.
VLC's recent UI changes have been a step backward (specifically making it impossible to see the playlist and the video at the same time), but at least you can queue things up to play.