Which is your favourite OS and why?

Just wondering what everyones favourite operating system is? I'm currently using windows xp home and I would have to say it's my favourite. I started off with windows 95 which was rubbish (good for it's day) then we jumped right to windows ME I believe which was an awful OS. I have used a mac before but I didn't really like the feel of their operating system.

I like windows xp simply because it's very easy to use, being a windows user for 10 years I know it like the back of my hand, every program works with it and I have rarely had any technical issues or the so called "blue screen of death" that haunts alot of users.

So this begs the question, what's your favourite OS and why?