My favourite would have to be Xbox Media Centre, I’ve probably used it most days since I modified my Xbox back in 2004. This application played a major part in my decision to originally purchase an Xbox and is the only reason my Xbox is still used today. At the time I wanted a way to play Divx/Xvid on the TV without using a PC, XBMC running on an Xbox was a perfect solution. When I later got a HDTV I realised it also made a great up-scaling media player too! XBMC also made me appreciate open source applications a lot more then did at the time, I won’t go on anymore but this is what the XBMC website has to say about it: Read More: here (Despite its name, ports for Windows, Linux and Mac are now available) So what’s your favourite open source application and why?