W007! Just realized my status has moved up to otaku! Huzzah!
I'm a cosplay h00r, so I would suggest ONLY cosplaying as a character who shares physical traits because it's about looking like your character, isn't it? Then again, I dye my hair, etc. to match my cosplays and some people don't like to.
It would be my suggestion to cosplay as a similar character, though, but do what ya like, ya know?