I was bored playin around with a leaked version of HL2, thought i'd take a pic of the startup menu and turn it into a desktop background
So:
Preview of my favourite one:
Links to that in nice PNG format:
http://www.icarusnetworks.co.uk/hl2bg2.png
Original colour background:
http://www.icarusnetworks.co.uk/hl2bg1.png
Enjoy