Original von lwatts
mplayer can play a lot of Quicktime content, if you have a recent version.
The thing is that if you go for example to http://www.apple.com/trailers/ you can't download the .mov but you have to watch it in the browser. So if there was a quicktime browser plugin for konqueror it would rock and you wouldn't have to look for a way to download the file to watch it.
Hopefully some day Apple will decide to port a konqueror plugin....