I watch movies on my Mac. I’ve been ripping my DVDs to DivX or h.264 to my hard drive simply because it’s easier to double-click a file than hunt around for a particular configuration of atoms. I used to use VLC for any files that Quicktime Player couldn’t play, but I’ve recently come across a better solution.
NicePlayer — “Quite simply, the nicest media player for Mac.”
Perian — “The Swiss-army knife for QuickTime.”