Microsoft

Microsoft, the world's largest software maker and easily the most recognizable name, has long been synonymous with its founder Bill Gates.

The man who has been the public face of Microsoft for the last three decades, announced in June this year plans to step down from his full-time role as CEO at the company.

With more than 600 million Windows users worldwide, Microsoft has expanded its range of products to include the software giant's first music player, Zune--which went on sale in the United States last week--to further counter archrival Apple Computer's dominance.

The Redmond, Wash.-based company broke new ground when it entered a controversial partnership with old foe Novell in November this year, to allow for greater interoperability between Microsoft's Windows and Novell's Suse Linux--a move which has received much criticism from the open source community.

Microsoft continues to battle security issues and faces mounting competition from open source and Google.