I know the video tended to focus on Windows or OS X, but Linux is also a viable option for producing professional audio. I've been using Linux for audio for several years now. I do use Windows for some things still (mainly, hosting certain sample-based plugins that don't have equivalents under Linux, like some of the EWQL libraries), but all of my scoring, sequencing and recording is done with Linux. I use MIDI-over-IP to connect the two (Rosegarden on Linux -> Reaper on Windows), and sending SPDIF back to the hard drive recording software. And I produce scores with a musical typesetting environment called Lilypond.

-- Brett