Six great YA books about female friendship

At the BN Teen Blog Natasha Ochshorn tagged six great YA novels about female friendship, including:
Ghost World, by Daniel Clowes

For a book written by a dude, this poignant, funny graphic novel sure gets it. The story follows best friends Enid and Becky through the summer after high school graduation, as they first continue on as normal, and then slowly drift apart. The book, more than almost