Since upgrading to Ubuntu Breezy 5.10, I found that video was broken in Firefox. I initially installed the MediaPlayerConnectivity extension I had used with Hoary 5.04 and disabled the Totem plugins for all video file formats. This worked well enough for everything except the trailers on Apple's web site. I suspect they're using the most sophisticated/"fancy" features of QuickTime, which causes Totem Mozilla Plugin—despite being disabled—to totally flip out and crash the browser. The Firefox UI doesn't provide any obvious way to uninstall the plugin, but it can be done. Here's how.
sudo rm *totem*
sudo rm -rf *totem*
I'm always wary of using forced recursive removal. I wouldn't recommend the second method, especially since the first seems to work equally well.
This should delete all files associated with Totem Mozilla Plugin. If you really wanted it back, I suppose you could reinstall the Firefox package. (You might have to use the one included on the Ubuntu installation CD.) The next step is replacing the Totem plugin with something else. The MPlayer plugin has improved considerably since Hoary, so that's what I'm using. The package is called mozilla-mplayer.* I opted to remove mplayer-386, which Synaptic will install by default, and replaced it with mplayer-nogui. I didn't want MPlayer cluttering up my Applications menu. I already had the necessary codecs installed because of xine. If you get a missing codec(s) error, you might have to download them from the MPlayer web site. Now everything works beautifully. Embedded media is a sweet, sweet reality for me.
* If I remember correctly, it's part of the multiverse repository. I can provide detailed instructions on how to enable repositories upon request.