I've started out with the easy books, but I did throw in extras. For instance, Winnie-the-Pooh by A.A. Milne is on the list, House at Pooh Corner is not, but was in the same volume so I read it too. Eeyore is a lot more sarcastic in the books, Kanga and Roo seem to have been additions to Christopher Robin's collection of stuffed toys and don't enter the book until later. Tigger isn't even in the first book. Rabbit and Owl seem based on live animals and are therefore more intelligent than the stuffed animal characters. But Christopher Robin is the most intelligent, taking on the role of a benevolent god in the Hundred Acre Woods. I went there a few years ago, and there are markers where various scenes in the book took place. It's not as impressive as one would hope, but Pooh Stick Bridge (pictured) looks much like the illustration--I wonder if the bridge has been replaced as it looked new.
The third classic on the list I read was the novella Breakfast at Tiffany's by Truman Capote. The book is much more liberal than the Audrey Hepburn movie, and more poignant with a very different ending. It reminded me a bit of a modern-day Camille by Dumas fils. (the basis for my favorite opera, La Traviata) in both plot and overall structure. The most notable difference to me when compared to the movie were the frequent, casual references to lesbianism--I can't imagine that being in an Audrey Hepburn movie. the edition I read also contained a few other short stories by Capote which are worth reading because they show his strength for character-driven short stories.
I supposed my conclusion so far on the Classics Challenge is that while reading a work by a classic author is good, reading two or three gives you a better understanding. I know that isn't a very profound observation, as it seems rather obvious. I guess another way to put it is that being widely read doesn't necessarily mean a wide variety of different authors, but rather a deeper understanding of each author. however, I think you do need to read broadly to find the authors you want to read more of, and be open to all types of books. You never know what you might end up liking.
I started the next book on the list, Agatha Christie's Murder on the Orient Express, last night. Though only two chapters in, I think she's another author I'll want to read several books by. Seems the goal of 20 books on that list (which lists one book by each of 150 classic authors) is going to be a bigger challenge than I thought, but a worthwhile one.