Who uses Macs?

I always get annoyed when I hear people say geeks use Windows.

My usual response is that geeks use Unix, and by default OS X.

My question to The Verge community is who uses OS X for science and especially computer science and related fields. The answer can be anecdotes of yourself and other people you have met, famous people, or entire companies.

For example, I'll start:

John Guttag, CS professor at MIT uses a Mac, I can attest from being in his class.

95% of Google employees I saw when I visited used a MacBook and 90% of the Macs ran OS X with the remaining on Linux.