Aerin, from The Hero and The Crown, by Robin McKinley. i love this book like i have never loved any other book. this was the first fantasy novel i read that had a strong female protagonist, and i just fell in love with Aerin. she's got a great sense of humor, which is largely what gets her through all the things that happen to her; she's strong and honorable and brave. i never get tired of reading this book.
Valancy Jane Stirling, from The Blue Castle, by L.M. Montgomery (who also wrote the anne of green gables series, if that gives you a hint). on her 30th birthday, Valancy wakes up and realizes that her life sucks and she's an "old maid", and then the doctor says she has a weak heart and only a year to live. this finally gives Valancy the courage to stand up to all her ridiculous relatives and say all the things she's always thought and go out and not be afraid to do things anymore (and, of course, find love with a wonderful man). her character development is just great, and she's wickedly funny.
i might do some more of these later, when the mood strikes me. but these two have always been my favorites.