Technically speaking, the house used as Eric Knox's bachelor pad was
actually a set created for the movie. However, it was based, as the
commenter below noted, on the "Chemosphere House" located at 7776
Torreyson Drive, Los Angeles.
: "...says "Charlie's Angels" director McG, who commissioned a
re-creation of the Chemosphere for the film...)
Google search used: ://www.google.com/search?q=%22Chemosphere%22+house++los+angeles,+ca&hl=en&lr=&ie=UTF-8&oe=UTF-8&start=10&sa=N
Using that search I found a link to
http://www.indydewey.8k.com/roadtrip.html which provided the address.
I verified the information by entering the address "7776 Torreyson"
into Google and found this description of the house which matches the
Chemosphere's unique description:
" "BODY DOUBLE" also features a number of other familiar Hollywood
landmarks: ...And that oddball, octagonal house-on-stilts where most
of the movie takes place isn't just a studio prop - it's real a real
home, and it's located at 7776 Torreyson Drive, south of Mulholland
Drive in the Hollywood Hills."