I recently installed a new operating system onto my PC, Ubuntu Studio version 8.04.  So far I have been very impressed.  It comes equipped with a wide variety of powerful open-source audio, video, and graphics applications.  For it’s price (FREE) you couldn’t ask for anything more.  The three programs that I’ve been using the most lately are Ardour (a digital audio workstation), Audacity (a multi-track audio application), and Gimp (a graphics program).  I plan to write more about each of these specific applications later.  For my audio work I use my Zoom Handy H4 recorder as an audio interface with a pair of Audio Technica 3035 mics.  Everything works flawlessly.  I would highly recommend Ubuntu Studio to anybody in any of the creative fields.