Mac OSX... probably moreso because I'm in the publications business... and my college matriculation took place during that whole "industry standard" thing. I was also raised in Silicon Valley (Sunnyvale, California), so access to Apple and Mac has always been a part of my education. I don't really have a preference. I'm to the point where an operating system is just another operating system. There are two Windows computers in my home as well. As long as the applications run and the documents can be converted, it's all good.