costume for comic con?

My boyfriend and I are going to comic con next month. To keep it from turning boring after the first hour or two, I told him that we'd be going in costume this year. So, now the question is what costume to use. I know how to use a sewing machine, so I don't have any problem making my own costume.

Everyone tells me I should just go as Wonder Woman, but I'm going to guess that there'd be at least two dozen other Wonder Women there. I would like to go as someone no one else is going to be dressed up as. What I was thinking was going as the Scarlet Witch and my boyfriend would be Quicksilver. But he doesn't want to put anything in his hair (Quicksilver has silver hair).

He said something like Black Widow and Daredevil would work. But Black Widows costume is so generic.

Does anyone have any suggestions for what would be cool to dress up as? The rules are the guy and girl need to be a pair and the costume can't be too outlandish and he wont dress up as anything that makes him look silly. And nothing that's going to have lots of others dressed the same (so no Princess Leah slave girl costumes).