What are the major differences between Linux and Windows Hosting?

When you decide to buy a web hosting plan one of the first things to be considered is the appropriate operating system. Linux and Windows are two major contenders here. Both OS have their own share of pros and cons. While Linux is open software the Windows platform is required to support specific applications. Besides, Windows enjoys a wide popularity across the corporate world. But how does it fare when it comes to web hosting arena? Which OS is more powerful and dynamic?