If you're a bit of a motor-head then perhaps you should give the Carbone Theme a try.
Carbone Theme changes the styling of the home screen on your Windows Mobile Smartphone to mirror a sports car's dashboard. After installing both the Carbone theme file and the digital clock file, a new background will appear on your phone.
The main image consists of a large clock designed like a speedometer with three smaller dials at the side, giving you access to information such as new SMS messages and missed calls. The graphics themselves aren't rendered particularly well and the Carbone Theme does look distinctly like a home-made effort rather than a well-oiled machine.
However, if you like cars then the Carbone Theme is sure to please.