I went as Vyvyan from The Young Ones but I didn't bother doing my hair special. Here's an album of pics my dad took of my little brother (the cowboy) and I.
http://picasaweb.google.com/thamnophis/Halloween2008#
Disclaimer: It says "hurt your dog" but that was just for authenticity. I've now written "don't" above it so that I can wear that jacket regularly.