Best QuickTime replacement!
It happens many time that QuickTime just cannot read some video files with weird codec. It is always best to have an alternative on hand and I must admit that I am not using this cool app as an "alternative" anymore. I don't know why but many video simply looks better with this app: VLC. It works in almost every operating system and it is free. The only complain I have is that the control are not in the same window as the video. It works amazingly well and like FireFox is a backup when Safari doesn't work, VLC is the same for QuickTime! More details and download here on the developer's site!