Bill Gates Office desk has three NEC-21" computer monitors (see picture) synchronized to form a single desktop. The screen on the left has a list of e-mails. On the center screen is usually the specific e-mail he is reading and responding to. And a browser (IE, ofcourse) is on the right-hand screen.

The richest man on earth talks in detail about his Office, Tablet PC and digital workstyle to Fortune. Read excerpts:

How Bill Gates manages millions of email messages everyday ?
Bill receives email only from companies or individuals that he has ever corresponded with. Bill uses Outlook Rules and Search Folders to sort emails. His assistants read the other email messages that don't reach his desktop.

Microsoft Think Week
During the Think Week, Bill Gates takes off from work and reads 100 or more papers from Microsoft employees that examine issues related to the company and the future of technology.

Bill Gates favorite Software
OneNote for note taking, Sharepoint for collaboration, Desktop Search Toolbar for finding relevant information on PC, servers or the internet. Bill Computers are loaded with Windows XP.

There are no papers anywhere but Bill Gates' Office does have a non-digital whiteboard for brainstorming sessions.

Related: Pictures of Bill Gates House - Take a virtual Tour

Source: Bill Gates: How I Work