Desktops look pretty and can be a great way to learn something new in photoshop. Hhmm... from these you can see I'm big fan of the hue/saturation control. Obviously, these have been resized as I run my work monitor at 1280x1024 and my laptop monitor at 1440x999 (yay for Macbook Pros and widescreen!).
Current desktops (one at work, one at home)
A few others favourites:
If you decide you want to stroke my ego and would like one of my desktops for your computer, get in touch with me. I'll resize one just for you :)