I think the best kids books are quite bizarre..
I love The Owl Service but it did also frighten me (mind you I read it when I was 8 I expect... )..
I went from non-reader, struggling in remedial reading classes at 5/6 to mega-reader, reading age of 25+ by 9 - bless that remedial reading teacher who came into our school twice a week, she absolutely unlocked it all for me!
I grew up in a house that was filled with books, books lined every wall, my friends told each other I lived in a mansion that was also a library (it wasn't a mansion either, it was a big victorian semi that was cold and draughty!) - because in their experience, books lived on 'the bookshelf' a thing they had one of in the house or if they were lucky, one in their room...
Once I could read I read EVERYTHING... The Hobbit, Stig of the Dump, Agatha Christie's, Nevil Shute, Dick Francis,... but mixed all this up with Enid Blyton (all of them!), all the horsey/pony stories from the 1940's on onwards... anything my mother referred to as twee, naff or rubbish... i devored it, alongside the childrens classics versions of Around the World..., 20000 Leagues..., Journey to the Centre of the Earth, Treasure Island etc.
I gave myself some nightmares, but the favourites stick with me.
Struwwelpeter... ahhh the pictures! Ugh! Brilliant!
The Hairy Toe - we FOUGHT over who got to read this in school, it was so popular.
Stig of the Dump - i never questioned why he'd be without any parents in a dump... he just was.
I earned myself zero popularity in secondary school when I read not just my english classes set texts, but everyones, and then started on other areas as my mums friend was head of english at a school in Wales... absolute book nerd!