I'm going to choose these mostly from fantasy/dystopia type novels so I'm going with the heroic/brave definition of the word instead of just being the female lead (because it would be impossible to choose if it were just all the female characters)--fantasy/dystopia has more opportunity for characters to be heroic than contemporary fiction. These are in no particular order:
Top Ten Favourite Heroines
1. Evanjalin from Finnikin of the Rock - She's just awesome. She's been through hell but she has this unshakable faith that she can make things right again for her people, even when people are doubting her. And even in other ways, like her relationship with Finnikin...I love how she is with that too (there's a specific example I want to give, but can't because spoilers).
2. Quintana and Phaedra from the two sequels to Finnikin of the Rock (Froi of the Exiles and Quintana of Charyn) - I'm cheating by having these two count for one, but I didn't want to have three of my ten be from the same series. Phaedra is a quiet kind of strong, she's kind and she holds her own even though she's in this unfamiliar place away from everything she knows...and she's willing to sacrifice her own happiness if it means helping her people.
And Quintana--she's fierce, and there's a wildness to her, and she endures so much to help people who have been nothing but cruel to her and have done little to help her in return...and she knows her own worth, in spite of people trying to tear her down, she's not always the easiest character to like but she's one it's hard not to respect (but I did actually really, really like her as well).
3. Celaena from the Throne of Glass series - I love that she's grown as a character. I love that she's a girly girl and a total bad ass (it bugs me when I see people act like the two have to be mutually exclusive, so I love it when writers show they're not). She's been through a lot, she's not always perfect, she's annoying sometimes...and I like that.
4. Hermione from Harry Potter - I don't think I need to explain this one. She's brave and she's unapologetically nerdy, she's protective of the things and people she cares about. If it wasn't for her, Harry and Ron probably wouldn't have even made it past the first book.
5. Suze from The Mediator series - Suze is hilarious and she's a girly girl who kicks ass, and she's brave in such normal ways too even though she's in an urban fantasy world where ghosts are real and she can see them.
6. Katniss from The Hunger Games - Katniss is an odd favourite for me, because she doesn't make the list for being a hero, she makes the list because she didn't want to be. All she wanted was to save her sister, that's how it all began. Then, reluctantly, she started to care more about other people too and she just wanted to survive and protect those people closest to her. She didn't want to be the face of the rebellion, she didn't want to start a revolution. She was always the reluctant hero. That's what stands out to me...there's plenty of characters in dystopian novels that are all about fighting for change, but Katniss was different. She never had a big goal of changing the world, she was always letting her heart and her instincts lead her.
7. Rose from Vampire Academy - Rose is another one of the kick ass girly girls. I love her determination to protect her friend. I love that she pushes herself to work harder, to be stronger, when she's fallen behind. She's flawed and brave, reckless at times but her heart is usually in the right place.
8. Jess Mastriani from the 1-800-Where-R-You series - I mostly like Jess because she's a normal girl. Yeah, she has this supernatural ability that allows her to save people, but she's kind of kick ass just on her own even without that.
9. Verity and Maddie from Code Name Verity - These are ordinary heroines, the book is set during the war, not in some fantasy world where they're kicking ass. I can't explain the specific reasons why they make the list, but they're both awesome in such different ways and both of them do things that are heartbreaking and ridiculously brave, I'm linking them together and counting them as one because what they do is so intertwined.
10. Mariam from A Thousand Splendid Suns - This is another ordinary heroine. She spent so much of her life unloved and endured so much abuse...surviving that is brave in itself, but then she goes above and beyond but I can't say more than that without spoiling it, but it's heartbreaking and I love her character.
Also, if you haven't read the books I mentioned, I really recommend checking them out (especially the books my first two picks came from, that trilogy is awesome).