I am using XP Home at home, and XP Pro at work. I've played with Vista a little bit, but not enough to really get a full feel for it. From what I did use of it, I wasn't too impressed...but like I said, I haven't really had much of a chance to really explore it. I was that way with XP when I was running 2000 Pro for the longest time and then switched to XP. I didn't think XP was as user friendly as 2000 Pro, but once I got it down and worked things out...I love XP now. However, I like the look of Vista...I just need more work with it.
I've never seen or let alone played around on a Linux system...I'd love to though.