TV shows
Buffy the Vampire Slayer- Buffy Summers herself. Strong, capable, develops into a determined leader. Rarely gives up.
Xena - Wrecking ball who doesn't put up with shit. Found something in her she wasn't proud of and steered herself into the path of justice into righting wrongs.
Books
OSI novels by Jes Battis- I've only read Night Child and A Flash of Hex - however Tess Corday seems to be a strong female character, Tess Corday a woman who's job it is to investigate occult crime scenes, and find the big bad monsters who go bump in the night. She's a bit of a girl at times, protective type, but that's not a bad thing at all, she draws strength from it. And while her partner will look out for her, and protect her, she's the muscle, she's the stronger of the two, and he's weaker.
Bram Stoker's Dracula - Mina - Maybe I'm in the minority, but I found Mina to do so much in Dracula. Almost nothing could have been completed without her. The big strong men throw the paper work to her, shove the busy work in her direction, she does it all and then some. Her organizing dairies, almost every bit of work she does helps their cause. I think she does the most to help the fight against Dracula than any other character.
Discount Armageddon by Seanan McGuire - Verity Price - Verity is a young woman raised to be a monster hunter/protector. Her family in hiding from the monster hunting crusaders - the Covenant of St. George, as outlaws helping the filthy cryptids (monsters, supernatural beings). She grew up in a home where the main concern her parents had where teaching their children how to survive encounters with the supernatural and hunters of the Covenant. And all she wants to do, is dance, professionally. A determined character, she's capable against fighting monsters, almost always on her guard, and while she loves outfits, the best outfit is the one with the most places to hide weapons.
Comis
Stephanie Brown - As Batgirl at least, cause I haven't read much of her other than that. As a bat, they're never really sexualized, 'cept Dick. She's one of those character's that screws up, picks themselves up, laughs it off, and keeps fighting. She has her weaknesses, she's not just a bruiser. When of her biggest weaknesses is bat on her chest, from it getting her into more trouble than she may be able to handle, to it getting into her head, and thinking she doesn't deserve the bat mantle, to her gaining confidence from the symbol, with determination and a smile.
Morning Glories - Casey - Getting into a top school, something she dreamed of, has come true, she has just arrived at Morning Glory Academy, and in her first week, they've tried to kill her, several times. Her response is to stand up, fight back, and find a way out, find a way to bring the school down.
Runaways - Most of the characters really. A group of teens find out their parents are super villains, run away from home, and decide the only course of action is to bring their parents to justice. Nico, the goth girl with a magical staff stuck inside her, the only way to get it out is to bleed - get beat up enough, cut herself, or if it's that time of the month. Nico's one of the bigger hitters of the group. Karolina is no push over herself though. and Gert may be vunerable, but she's got spunk, and a pet dinosaur.
Cardcaptor Sakura - Sakura - A young girl, a lot of powerful creatures, and a staff to catch them. The forces of the cards are always bigger than her, they surprise her, take her friends captive, find ways to disorient Sakura, and she keeps fighting, and finds a way to win.