[hackermom]

And in the OS X context the better form of it, MPlayerX: http://mplayerx.org/

[Groxx]

Which has taken over Perian / VLC almost entirely, for me. Perian has been utterly fantastic, a near ideal passive improvement for everything, but MPlayer smokes everything in performance.

[thetinguy]

I find mplayerx extended better:

http://www.mplayerosx.ch/