My friend keeps threatening to go to a con dressed as Man-Faye or Man-Revy. That would result in the loss of some sanity points.
My most elaborate costume was a t-shirt with an iron-on logo, the Section Nine symbol from GitS: SAC. My dream costume is a 100% correct Colonial Marine Corps uniform, armor set, and M41A prop rifle. Considering the fact that the camo pattern used was created for the film, I know I could never be completely accurate, but I could get pretty close. It would still be serious $$$.