MPlayer OSX Extended offers more options and has actually been updated recently.

http://mplayerosx.sttz.ch/

Note: mplayer logs names of files it has played, in console.log, located in /Library/Logs/Console.
(ie: system folder, not the user's ~/Library folder.)

MPlayer can also play RealVideo and RealAudio if you install the optional codecs package.

i wish there was such a thing as vlc + mplayer, but until then i have them both..

Viewing WMVs with Flip4Mac: open instantly but loading takes ages, or wait for QuickTime to load whole movie and you can seek. Viewing them in VLC: open instantly and seek works, but can't determine the keyframes, so the action kind of smudges out till the next keyframe hits. MPlayer opens instantly and seeks instantly and correctly. Second cool thing: MKV files from HD material opens instantly and seeks instantly. VLC crashes every once in a while when opening these files.

</br>
Download the latest unofficial builds here:

<a href="http://www.haque.net/software/mplayer/mplayerosx/builds/">http://www.haque.net/software/mplayer/mplayerosx/builds/</a>
</br>

Imho MPlayer is the fastest player to seek in movies.
Plus, it has convenient keyboard shortcuts for that (left/right/up/down arrows). VLC is slower to seek, and doesn't allow (unmodified) arrows as keyboard shortcuts, making it less convenient.

The command-line version of Mplayer can easily rotate a movie, eg:
mplayer -vf rotate=1 mymovie.mpg
will rotate clockwise, see mplayer's documentation for more info.
The command line mplayer is included, and can be found here (for the intel version):
/Applications/MPlayer OSX.app/Contents/Resources/External_Binaries/mplayer_intel.app/Contents/MacOS/mplayer

Way better then VLC.
See my comments @VLC and Perian for the reason.

Seems smoother than vlc, but the normal interface that other apps have (double click for fullscreen, move the mouse in fullscreen to see player) aren't there, so I got turned off.