Well, since this thread’s been kicked up the pile again…
Someone mentioned Kate Di Camillo earlier. I bought Despereux for my 6th grade daughter for her birthday. Then I sat down over a cup of coffee and inhaled it in a couple of hours. Yum! Then I gave it to the Taller Girl and she inhaled it over the course of the first day, in between lessons. Yum! Fantastic book - just as well she got other books for her birthday too, though!
The Master of the Grove by Victor Kelleher
Won the Children’s Book Council of Australia Book of the Year back in 1983! I read it in Year 6 and I’ve just started reading it to my son - it’s still a cracking read.
Scott Westerfeld’s Leviathan trilogy http://www.amazon.com/Leviathan-Trilogy-Scott-Westerfeld/dp/1416971742/ref=sr_1_3?ie=UTF8&qid=1441580762&sr=8-3&keywords=leviathan
A sort of steampunk recasting of WW1:
I’ve recently discovered that “Ella Enchanted” has the mark of death on it, er, I mean the “Newbery Medal” imprinted on its cover. Could this be the Holy Grail of Newbery Award winners (a winner that isn’t ungodly tragic and depressing?)
I don’t have time to reread this thread, but has anyone (including me) mentioned Larklight by Philip Reeve yet? It’s brilliant.
I remember “The Halfmen of O” from when I was a kid
My nephew recently studied Percy Jackson for literature - but I’m not so sure about that
I second Holes - anything by Louis Sachar, actually.* The Cardturner *was phenomenal. It deals with some serious themes/plot points (old age, blindness, relating to weird old relatives, stubbornness, true love) while being engaging and upbeat. I want to go re-read it now.
How about the Horatio Hornblower series? They’re aimed at about middle-school aged kids (maybe a little older).
The book that scarred me the most as a YA was Bridge to Terabithia. I bawled all night when I finished that one. Don’t do that to those poor kids.
I’m sure you’ve made your lesson plan already and this is too late but I love YA lit and am only moderately ashamed of myself for it 
Gets my vote.
Or The Amazing Maurice and his Educated Rodents. (Note, does have one snuffly moment)
Ooh, ooh! The View From Saturday is really good.
Yes–it’s amazing. I read it to my students every year, and I’m not making this up, every year when I reach the end, my students break into spontaneous applause. This doesn’t happen with read-alouds: kids love them, kids respond to them, but the applause at the end? It’s peculiar to The Tale of Despereaux, in my experience. The language of the book is perfectly beautiful, the character arcs are multifaceted, the plot is complex, there’s foreshadowing and symbolism. It’s excellent for lit study (I use it primarily for character arcs with my students, but I also talk about a lot of other things with it as well).
Incidentally, I want to mention that it’s been six weeks since I told you all to go out and read The True Confessions of Charlotte Doyle. The fact that none of you have come back to this thread gushing about what a kickass adventure yarn that was proves that none of you have followed directions. What gives? GO READ IT NOW!
Back when I was in sixth grade, the 1966-1967 school year my teacher introduced our class to The Hobbit. Mr. Bradbury was cool, it was his first year teaching, and he liked scifi and fantasy. I was sure I wouldn’t like the book he was reading to us, one chapter a day. Then I realized I was looking forward to the next day, to hear more.
Tolkien may seem old hat now, with the movies and all, but as my first exposure to fantastic literature it blew me away. I kept looking for more, and I can never thank Mr. Bradbury enough for what he did. BTW, I had the chance, at his retirement party, to tell him about this, so he knows I appreciate it.