The Phantom Tollbooth is a big one for me - big enough I've taught it 6/10 years I've taught. It is my biggest regret moving down to 2nd, they are too inexperienced to really get a lot of the deeper connections without a lot of backfill which would ruin the pace of reading.
Narnia is another. My mother read them to my older siblings but I was too young to really get into anything with chapters, and then it took me a while to learn to read. Once I did I would sneak into my parents room to lay on their water bed and read them. That poor box set (which, unlike the newer ones followed the PROPER reading order of The Magician's Nephew after The Horse and His Boy, and before The Final Battle) fell apart in my hands. I now own two box sets- because it is IMPORTANT.
Winnie the Pooh was my other one. Like Narnia this one sat on my mother's headboard instead of the bookcase. I loved reading those books.
Now... if we go into picture books... I could go on forever. As I've grown up more I've realized some of them have not aged well though, so they are retired to a box of 'aww, good memories but woah, racist as fuck, set aside and never read to the next generation.' (5 Chinese Brothers being the most recently added when I came across it in a second hand bookstore.)
