Among the Hidden, Margaret Peterson Haddix - the first in the Shadow Children series, this is our introduction to Luke, an illegal "third child" in a futuristic America where the government has made it illegal for parents to have more than two children due to a food shortage. It's much easier to see its scathing political commentary on China's population laws as an adult reader - the book isn't subtle - but what I like is how Haddix presents at least four distinctly different responses to the totalitarian regime, but doesn't present any one as being unequivocally right.
The Circle of Magic quartet (Sandry's Book, Tris's Book, Daja's Book, and Briar's Book), Tamora Pierce - Her books set in Emelan aren't nearly as well-known as her books set in Tortall, but they're still well worth reading. By now she has two quartets and several stand-alone books set in Emelan, and while this first quartet is more kids-y than her Tortall books, she ratchets up the age of her intended audience significantly with the following books. In this book, four children from very different backgrounds, classes, and races are thrown together as they discover that they have craft-magic, meaning that unlike the academic mages who learn their magical abilities through books and study, they work their power through nature and creative activity. Sandry has thread-magic (spinning and weaving), Tris has weather-magic, Daja has smith-magic (metal and fire) and Briar has plant-magic. Each of these books focuses on a different member of the group, but the real strength of the series is the evolving relationships between them. My one quibble is Pierce's frequent asides denigrating academic study (I think my book-work is important too!)
Three of the Dear America Diaries (Across the Wide and Lonesome Prairie, I Walk in Dread, and Standing in the Light), assorted authors - these well-researched historical fiction novels were a big part of my childhood. Not only did I read them for my own enjoyment, but we read a few in elementary school as a part of our study of American history in general and New England history specifically (for example, after reading the diary of the mill girl, we went on a field trip to see some of New Hampshire's historical mills). Across the Wide and Lonesome Prairie relates the story of a girl following the Oregon Trail, moving with her family from Missouri to Oregon in search of a better life. I Walk in Dread was not yet published when I was a kid, but if it had been I'd have eagerly snapped it up - it's about the Salem Witch Trials and I sought out everything I could get my hands on about that terrible time in American history. I read I Walk in Dread shortly after reading Arthur Miller's The Crucible, and while Miller's play is a much more dramatic narrative, it's also rather one-sided, seeing small-town land politics and community fear as the only contributing forces. I appreciated how the Dear America version of the trials is much more comprehensive, noting fears over deteriorating, increasingly violent relations with Native Americans, instability in the colonies' political relations with England, extremely misogynistic gender relations, and strict Puritan ideas of morality and the devil. Finally, Standing in the Light tells the tale of a girl kidnapped by Native Americans, who grows to love them and their ways.
Harriet the Spy, Louise Fitzhugh - this was a poor choice of library reading on my part. I didn't like the book as a child, and turns out, I hate it even more now. Apparently the solution to losing friends when your secret nasty comments about them are revealed is to publicize your gossip in the school newspaper, and somehow that makes everything all right...?
Princess Academy, Shannon Hale - I'm really sorry to say that I didn't like this book (sorry Amy!) Maybe I would've liked it better when I was in the target audience. It's not that the world-building was poor, but Hale falls prey to a lot of standard fantasy tropes (including the really annoying, obviously fantasy made-up names). Most of all, I was bothered by this picture of gender relations, such that every girl between 12 and 17 could be forced to attend the princess academy because it has been decreed that the prince will choose one of them for his bride. Where is their agency? Where is their choice in the matter? Yes, the academy basically turned out to be a school, which was great for this under-educated territory, but I couldn't get past the fact that the girls were compelled to wait around to see which one would be chosen as a wife.
Tuck Everlasting, Natalie Babbitt - This book seemed much longer when I was younger! It's a really interesting tale about a lonely girl who encounters a family who accidentally made themselves immortal by drinking from a magic spring. Now they must conceal themselves and this spring from any who would take advantage. Not only is there some great symbolism (the toad in particular), but also wonderful musings on family and relationships, time and mortality, and living one's life in a meaningful way.
Artemis Fowl books 6-8 (The Time Paradox, The Atlantis Complex, and The Last Guardian), Eoin Colfer - The Artemis Fowl books are awesome and I highly recommend the first three in particular. Book 4 gets crazy dark and depressing, and books 5-7 in this series kind of lost their way for me; they're unevenly paced and not as well-plotted. But the last book in this tremendous saga about an Irish villain who must continually team up with the fairy police of the Lower Elements in order to save the world was a triumphant return to the very best of Colfer's craft. I loved how the series came full circle, both beginning and ending with sieges at Fowl Manor - by this second siege, all of the relationships between every single one of the characters have evolved dramatically and it was so cool to see.
And this is my newest stack of children's and YA books. Of these, I've only ever read three, so I'm hoping the others are good!