Perian is great, but the current version has some issues with the latest version of QuickTime Player (not QuickTime itself, just QuickTime Player). So if you use Perian you may prefer to use an alternative QuickTime-based player like NicePlayer.
The big advantages to Perian is that A) videos will work in any QuickTime-compatible software, and B) it has MUCH better Subtitle support than VLC.
MPlayer OSX Extended is another option. It's a standalone program like VLC, and it has great subtitle support like Perian. Not as polished as VLC, though.