Evangelion Rei vs Asuka dbate, I've been really intrigued by the newly-added third female option (amongst the pilots, anyway): Mari Illustrious Makinami. She's got a really cute design, but I still haven't heard much about her personality. alafista's post with some stellar Mari cosplay reminded me of the character, so I thought I'd let you know a few things about her that I've discovered since the last time she came up (though probably none of it is "new").
Mari was actually first revealed, at least in name, in the Petit Eva@School DS game, then in movie posters sans name, and her full name came out in an Evangelion-focused magazine. Prior to that she was known only as "meganekko." She pilots both EVA-05 and, at some point, EVA-02, which seems to imply some relationship to Asuka-- though it's hard to imagine Asuka giving up the EVA-02 easily. She seems to know Ryoji as well (I'm totally picturing some major Asuka rivalry here), and may be a spy for one of NERV's other branches.
The cosplayer, by the way, is one Chamaro-san, who is also known for her awesome Haruhi cosplay.