If you like the color orange then you might want to give Curlyfire a try.
This Windows Mobile theme will transform your Pocket PC with a vibrant new orange skin that will make your device stand out from the pack. The new background wallpaper in Curlyfire consists of an abstract image of glowing blobs and bright orange spirals.
Besides just adding a new background picture, Curlyfire also changes the color scheme of Windows Mobile, adding orange top and bottom menu panels and a yellow Start menu bar.
Personally, I found the whole thing a bit garish, but Curlyfire is certainly an eye-catching theme nonetheless.