QuickTime add-ons? How to tell what's needed? I've been chatting on Chatzy via Firefox on the Mac lately, and every time I go there I get told that I need to update QuickTime components. Here's the dialog that comes up:



It then links me to this site, which offers a range of addons. However, there is no indication which of these things I need to run the page. I don't want to install all the extensions, obviously, but I would like to get the one I need. Is there any way to tell what's lacking?
Perian is frequently chosen, for being complete and suitable. A lot of people say it's one of those things you should put on every new Mac. VLC has browser plugins, but I've never noticed Perian not handling everything (not sure I would know, neither are bloated).