Paksinarian Dorinsdotter! I can't remember if this is what the book is called, but I read it forever and a day ago. The main character is a young woman(Paks)who goes off to become a mercenary to help make money for her family. I don't remember any more than that, except that she kicks ass!

There's also Angua from Discworld. She's one of my favorites. And, seriously, Donna Noble from Doctor Who. She's very much a woman, but is one of those strong, very sure of herself women. She's a little ridiculous, but fainting buttercup who does nothing she ain't.