Mine would win as the absolute most boring, if I could only post a pic.
The background is grey. I find grey is easiest on my eyes in dim/dark rooms. No wallpaper, no tiles, just flat dark grey.
There's no icons on the taskbar at the bottom except the start button and the clock. Nothing in systray at all. Taskbar is grey too, none of that fancy blue color and it just sits there and doesn't auto-hide or play games like that.
4 ICONS on the main desktop--My Computer, Network Places, Internet Explorer and Recycle Bin. They're on the left where they default to (don't want anything flashy like...moved icons).
My computer itself is probably the most interesting though. I took all of it out of the case for repair work on the fans and never put it back together, so it's just a mess of cables and boards and parts and drives sitting on various levels of my desk and on the floor. I ran over the power supply (it's taken apart too) with my chair once and it sparked a lot and shut down, but it still works ok. I found that in its current state it runs far cooler than when it is together. I'll probably get it back into one piece this winter since cooling won't be such an issue and it's getting kinda dusty.
J_A_B