I know I promised Good Parents (harder than I'd thought to find 'em), and I swear I'll do it next time. But right now I want to suggest another way to stay on a princess-y path, but read more varied stuff.
King Arthur and other stories of brave knights, many of which include princesses.
I'll start with one of Lizzie's early favorites, Young Guinevere, a picture book by Robert D. San Souci. It's a little off from the mainstream Arthurian stories, but it's about a princess who runs around in the woods and shoots bows and arrows and does stuff. Ends with her going off to marry Arthur. Out of print, alas, but I've included an Alibris link here.
You've talked about Trina Schart Hyman with your Rapunzel entries. I'm fond of her art, and she has some very good illustrations for stories of knights and ladies, several of them done for retellings by Margaret Hodges, . I'll start with
Merlin and the Making of the King, which is structured like an early chapter book, and gives some of the basic Malory stories, with lush illustration. A good introduction the the sword in the stone story, Morgan Le Fay, Lady of the Lake, Mordred and the death of Arthur. I think it skims pretty lightly over Guenevere and Lancelot.
Hodges and Hyman also collaborated on two great picture books:
Saint George and the Dragon is a retelling from The Faerie Queen. Hyman won the Caldecott Medal for best illustration for this one. It gets a bit gruesome at times: St. George does in the dragon rather graphically. And if you happen to get this (I have no copy of it here in Maine, so I can't scan, alas), the elderly medieval couple on the back cover are portraits of the author and her husband, with the Green Mountains of Vermont where both Hodges and Hyman lived in the background.
The Kitchen Knight, about Gawaine's brother Gareth and the sisters Linette and Linesse, neither of whom one could call a shrinking violet.
And just because I'm on a roll with Trina Schart Hyman, I want to include two others of hers:
Bearskin, written by Howard Pyle, now out of print. About a young man raised by a very loving bear who must accomplish various tasks to win the hand of the princess he loves. What makes this edition of the story so special is that Hyman has given a wide range of ethnicities to the characters: the prince is Asian, the princess is black, her parents and the members of the court are a melange of many colors, all with lots of personality.
And on the subject of non-wimpy princesses, one last book, for an older crowd:
The Serpent Slayer illustrated by Hyman and written by her daughter Katrin Tchana. It's a collection of retellings of fairy tales from around the world which showcase strong and fearless women. Some of them pretty intense, as you can see from the cover.