I’m fond of The Weirdstone of Brisingamen, an early YA novel by Alan Garner. I’m American, but from what I’ve read, Garner became successful in England writing fiction that incorporates British folk lore.
One of my favorite books from the days of reading to my daughter is Holes by Louis Sachar. It won the Newberry and was made into a movie featuring Sigourney Weaver (as a baddie). The film is decent, but of course the book is better.
I gave my copy to my daughter when she was 11 and she still has it. Hopefully her grandchildren will follow suit.
Are the books by Neil Gaiman YA? Coraline, The Graveyard Book, Stardust.
I also recommended Stargirl, but will go one step further. Get the audiobook that is read by John Ritter. He did a terrific job and it takes a great book and, I think, makes it really come to life.
His book Winterdance is great, but is not for kids. It’s the adults version of Woodsong and was the best book I read in whatever-year-I-read-it. I loved it. Have not read his re-write for kids, which is what Woodsong was.
When my kids were little, they’d come home from their school’s Scholastic Book Fairs with all sorts of good stuff. And often have me read it to them at bedtime.
Well, we all got hooked on the Animorphs books. I loved them: there was a lot of animal facts (the kids could “acquire” the DNA by touching an animal and changing. When the kids became dolphins, all they wanted to do was play, becoming ants was scary because they lost their individuality. And when Jake became a golden retriever, it was almost impossible to focus on anything*…)
*“Okay, I’m com… ohmigosh, a squirrel walked across this sidewalk yesterday. This is THE MOST EXCITING thing ever! And there’s a woman with a stroller. That’s exciting… okay, I know we have to go. But look! A boy walking a dog! That’s THE MOST EXCITING thing ever!” etc.
And there was serious science-based sci-fi. Some of it a bit dark, but my kids thought it was cool that the evil alien species would spread themselves out over someone’s brain and take over.
Anyhow, by the time the kids outgrew the series ‘round about Book #30, it had been wrapped up at #52.
Of course, I had to find out what happened next, so I finished them (much to the kids’ amusement). They were short books, it was easy.
It was a well-written, satisfying ending, and I often reread the last two books for fun.
I think Coraline is children’s, The Graveyard Book is YA, and Stardust is standard adult.
I responded earlier with books I remembered reading as a kid, but for newer stuff, you can’t go wrong with any YA by T. Kingfisher. (Her adult books are great also).
A Wizard’s Guide to Defensive Baking is an example; I’ve heard good things about Swordheart as well. 
May have read something by Clyde Beatty. He was the Lion Tamer.
There’s no way I’ll remember my long list of favorites, but putting aside series (like The Hardy Boys or The Three Investigators or The Great Brain or the Susan Cooper books), here are ones I can recall with love, off the top of my head:
I’m pretty sure more will occur to me the moment I hit Reply, but it’s a start.
I’d never heard of this growing up, but our book club facilitator for many years was his daughter, so I ended up reading it and liking it a lot. I don’t think I got to the sequel, though.
Joyce is terrific.
There was a book I read in high school called When the Legends Die. It made a huge impression on me.
A movie based on the book came out a year or so later, but it it was nowhere near as good.
I did read a book by him as well so I surely confused them.
Gaiman kind of sucks, even though he is a great guy and I like a couple things from him. Except for Sandman and Good Omens, I have not been a fan. Graveyard Book was way overrated, for example. Ocean at the End of the Lane was a rare book I almost quit on.
I mentioned reading at bedtime to my kids. We read everything, but heavy on adventure (Journey to the Center of the Earth, Treasure Island).
But the most exciting one was a surprise to me: Tom Sawyer.
It was the scenes of Tom and Becky lost in the caves, with Injun Joe stalking them. Twain really got across what being lost in utter darkness would be like, with deceptive echoes when you’re separated from your partner.
.
(Feel free to refer to First Nation Indigenous Native American Joseph if you prefer… but I was too scared at that point to care.)
I don’t think the distinction between children’s, young adult’s, and adult’s literature is very clear, and I don’t think it’s very useful. The interesting thing for me is that I didn’t read much young adult’s literature (either fiction or nonfiction) after about the time I was nine years old. I started to read some adult’s books (in terms of how difficult the material was, not in terms of it being too concerned with shocking subjects) at that time and apparently decided that I didn’t need to read anything less difficult anymore. Because of that I read a lot of adult nonfiction after that point.
I didn’t get back to reading anything aimed at children or young adults until much later when I began giving such books (usually obtained quite cheaply) to my nephews and nieces and later grandnephews and grandnieces for Christmas presents. One thing I have now is a list of 38 “children’s fantasy series”. Not only do I give the list itself to them, but I give a few of the books to them each year. I started compiling this list because I was annoyed that people talked about the Harry Potter books as if it was clearly the best such books. I don’t think so. It’s not bad, but it’s somewhere around the middle of this list as far as my preferences go.
Many of the series on this list have already been mentioned. One that hasn’t is what I call the A books by David Levithan (although neither Levithan nor the publisher has given a name to the series). This series consists of Every Day, Another Day, and Someday, so far at least. The series is about a character called A. I recommend reading Every Day for everybody.
Another author whose books I’d like to recommend is Michael Morpurgo. He’s much better known in the U.K. than in the U.S. (Although, strangely, there’s a movie adopted from his book War Horse which was directed by Steven Spielberg.) I heard about his books first during a visit to a place called the V&A Museum of Childhood (now about to re-open as the Young V&A Museum) in London. I like one of his books I bought there, so I bought very cheaply a bunch of his books after that.
I liked Robert Cormier’s grim little epics other than the Chocolate War novels, and still do. After The First Death, Fade, We All Fall Down and Tenderness are fast, hard-hitting reads I’ve enjoyed going back to as a grown person.
I read a lot of the Hardy Boys and Tom Swift, Jr. In elementary school and my grandmother paid for a subscription to Landmark Books and All About books.
YA did not exist as a marketing category and by 6th grade I was reading Groff Conklin’s SF anthologies. By 7th grade I thought Isaac Asimov was my favorite author (I never read any of his Lucky Starr books, though). I was a big fan of Kurt Vonnegut in junior high; Cat’s Cradle blew me away. Robert Sheckley was also a favorite. Read Heinlein, starting with Stranger in a Strange Land but didn’t get to his YA stuff until after college.
This is approximately what happened to me too.
Henry Reed, INC.
All the Archie Comics (which Mom used to teach me to read).
Hoo boy, I avidly read Piers Anthony when I was young. Particularly enjoyed the Apprentice Adept and Incarnations series (although, typical of his work, they got significantly worse as the series went on). But looking back on it, his work was always problematic and grew truly disturbing as the years went on. He’s apparently still churning out the Xanth novels, although no publisher will touch him.