I never come across anything I want to watch that needs Quicktime
Actually I think I probably have a codec loaded so maybe that's why I've never come across anything needing it
DivX or Nero probably loaded it, although there's been a fair few codec packs loaded on this machine so who knows.
Edit - for those thinking "what is a codec" it is short for
coder/
decoder. It is basically a set of instructions as to how to turn a (usually) compressed video (or audio - eg MP3 is a codec) file into something we can watch and vice versa.