Bill's house is not all that big...and definitely does not feel that big. I work for Microsoft and Bill's house is about 56,000 sq feet but is more a complex of small building spaces tied together by a series of hallways. It is built not just as a residence but as a place for meetings and receptions so most of the size is not directly living space.
He built it specifically to feel small and intimate to the individual while in some other part of the complex there can be a group gathering going on. The house is built into the side of a hill overlooking a Lake in Bellevue which is a Seattle suburb. You can not see most of the house from the road and only some parts of it are viewable from the Lake.
The interior is done in alot of natural woods. He used beautiful salvaged old growth Douglas Fir, Sitka and Yellow and Red Cedar for much of the beams and exposed woodwork. Some of the timbers are 8x18, all salvaged old growth...
I have worked for Microsoft for 10+ years which has given me the freedom to build as well as I can. I tell people that I have known Bill since he was only worth 8 billion!!
Bill appreciates good music but it is Microsoft co-founder Paul Allen who is an active guitarist. He still plays in a classic rock band. He collects fine and vintage guitars. I have played with him but have never worked up the nerve to sell him a guitar.