Costumes are so fun!

So this year we have a friend hosting a superhero costume party, as his birthday falls right before Halloween. So, of course, I'm trying to come up with something really cool and unique. I really want a costume that no one else there will have.
I was brainstorming a bit at work with my friend, and came up with a few cool ideas.
I really like the idea of Buffy the Vampire Slayer (she's a superhero...sort of... well I get to have cool stakes! So there!) with the cheerleading costume and a belt of wooden stakes.
Then my friend suggested Ghost, who I had never heard of... But this costume could be so great.
I did always like Jean Grey, though. But the costume doesn't look very original...
Or maybe.... Captain Planet! Earth! Wind! Fire! Water!
What do you think? I can't decide!