Lust. Even if I could pick a military woman, it would still be Lust. She was actually my first ever female character crush waaaaay back during the first FMA series (and one of my all-time favourite female character in any form of entertainment). Up until then I was generally indifferent towards female characters and preferred male ones. While I liked what they did with her in the first series, she was even more badass in the manga and FMAB.
Don't get me wrong, I would not want to be caught anywhere near her because it would probably = me dead, but I can admire from afar. Wish I could cosplay her, but um... I don't think I'm well-endowed enough for that. :C
Then again, I think FMA has a really, really solid cast of female characters. I can't think of a single one I actually dislike. (But it has an equally-strong cast of male characters, so it's just good all around).