I've gone through many video players as my "choice" application for that purpose. Initially it was Xine, then VLC, then back to Xine. I have always said that if mplayer would just have a nice robust front-end that wouldn't crash/freeze/jack up like all these other apps tend to do, I would use it.
Since the release of Hardy I've been using SMplayer and so far it's been flawless.
I can NOT say as much for Totem, ever. Ever since I used Fedora, Gentoo, and even SUSE as a main desktop, Totem has just failed. Whether it be codec issues, or crashing, freezing. When I try to fast forward on WMV or AVI or ASF files, it still will often freeze or lock up my system to where I have to go to tty1 and kill it.
In all, Totem in literally ALL of my experience on different systems whether they be systems for work, friends, acquaintances, family, myself; suffers from:
-> crashing and burning
-> freezing my system
-> just simply not working with some files
-> no obvious way to use subtitles
-> no obvious way to easily change the video deinterlace mode
-> an annoying side panel
SMplayer and VLC just put Totem to rest.
When I try to get my parents to use Linux over Windows, simply because all they do is check email and browse www, Totem was the bane of that effort. I would change the default app for files to something else, but EVERY time my mother had an issue playing some video file she got in email, Totem would be sitting there staring at me, unable to play. Even though I configured the codecs correctly, and other players would play it without a hitch. It just seems that *Some* files don't work, while others do. The WMV's that I find work, but the ones that she receives in emails don't for some reason. But in mplayer it works perfectly. In VLC perfectly.
mplayer has been considered the "best" media player by many popular sources. It's open source. And the only problem I've EVER had with it is the interface which is now just as good as VLC with "SMplayer". And it's in the Ubuntu repo, so why not?