Pride and Prejudice has long been my favorite Austen, but after several rereadings, I think that Persuasion may have overtaken it at the top of the list (or at least equaled it). The heroine, Anne Elliot, is quiet and unassuming and the story of her romance with Captain Wentworth could hardly be more different from that between Elizabeth and Darcy, yet it is perhaps more deeply felt and written.
The story begins eight years after Anne, on the advice of her friend Lady Russell, broke off her engagement to Captain Wentworth; now, at twenty-seven, Anne's "bloom [has:] vanished early" and she is nearly an old maid. When Anne's father, Sir Walter Elliot, is forced to rent out their family estate, Anne goes to live first with her married sister Mary and then with her father and unmarried sister at Bath, and Captain Wentworth returns to the scene. The resulting renewal of their romance unfolds gently and tenderly, culminating in a deservedly famous scene in which Anne, debating with Captain Harville within Wentworth's earshot, movingly defends the emotional capacity of women: "All the privilege I claim for my own sex (it is not a very enviable one, you need not covet it) is that of loving longest, when existence or when hope is gone."
I imagine that when asked which of Austen's heroines is their favorite, far more people would choose Elizabeth Bennet or Emma Woodhouse than Anne Elliot, yet I find Anne particularly sympathetic - a woman of deep sympathies, common sense, good judgment, and self-awareness. Her journey from resignation to joy is beautifully and sympathetically delineated by Austen, without the loss of her usual sharp wit.