I probably read all of these as a kid. They used to have a huge rack of them at the public library. Glad to see they are still produced today, but the artwork of the original books is far superior.
If we're talking young adult years, then it was any of the short story collections from Steven King. So many of these stories were turned into movies. I should probably read again since it's been so long.
And if its my favorite book ever? Flip a coin on Orwell. I can't tell you how many times I've read both of these classics.