Microsoft's Bill Gates, Brilliant technologist, great philanthropist, ruthless businessman, founder of Microsoft, will mark the end of an era today as he signs off the software company which was he founded with Paul Allen 33 years ago.

After devoting decades at Microsoft, Gates is dedicating himself full time to the Bill and Melinda Gates Foundation,which has 543-strong team.

The Gates family home is a 40,000 sq ft mansion in the suburb of Medina, on the shores of Lake Washington. It has a library, with a domed reading room,a garage, a pool, with enough space for 30 cars, speakers hidden beneath the wallpaper, portable touch pads that control everything from TV sets and the lights to the temperature. The total value of the house is estimated at $113m – the annual property tax is just over $1.After wedding, Melinda got her own architect in and changed the house into a tranquil family home for them and their three children, with more cosy spaces and fewer boys' toys.