for other Cover Love, check out Hunger For Knowledge's Draculas and Carpe Librum's Sunne in Splendour . ETA: 20,000 Leagues Under the Sea By Nostalgia Reader; and Mayor of Casterbridge by Books, Hockey, and a Bucketful of Snark
Wizard of Oz was one of my childhood favorites. It has been published under both titles: Wizard of Oz, and The Wonderful Wizard of Oz. Here are several covers featuring illustrations by the original artist, W. W. Denslow:
ETA: this one mentioned by Hyzie, aka Primrose, in the comments:
The pages are Emerald City green.
And several from the movie:
The story has inspired other artists over time who have added to the repertoire:
I love these gorgeous art-deco inspired covers:
Also these very contemporary ones:
These emphasize symbols:
And here are some specialty covers:
Both of the next two highlight the objects of the quest: brain, heart, courage and home.
I liked this one quite a lot:
but this one's kind of terrible:
It's kind of funny that, although the book describes the slippers as silver, the movie's portrayal of them as ruby seems to be the image that has stuck:
There're about a million other book covers out there; some amazing, some very crappy.
these are among my favorites. (Except that one, up there with the brain.)