I don't believe anyone has yet mentioned the foundation trilogy by Issac Asimov. This "trilogy" has become 6-7 books by now, but I am referring to the original 3 books. They are a collection of short stories that all relate to each other. They are pretty amazing.
SciFi:
The Foundation Trilogy by Issac Asimov (as mentioned above)
"The Time Machine" by H.G. Wells
"The War of the Worlds" by H.G. Wells
Books written by Ray Bradbury
Fantasy:
The Chronicles of Narnia by C.S. Lewis
books writteny by J.R.R Tolkien (as mentioned previously)
Other:
The Bible
"The Great Divorce" by C.S. Lewis
"Animal Farm" by George Orwell
"A Christmas Carol" by Charles Dickens
"Through the Looking-Glass" Lewis Carroll
More recent books that are thought provoking:
SciFi:
"Hyperion" by Dan Simmons - on who or what makes God, God.
"The Gap into Conflict : The Real Story" by Stephen R Donaldson - whole series is on manipulative behavior
"Callahan's Crosstime Saloon" by Spider Robinson - a collection of short stories; great story telling.
Fantasy:
"Wizards First Rule" by Terry Goodkind - the wizards rules apply to real life.
"Magician: Apprentice" by Raymond E Feist - best epic fantasy since the Lord of the Rings, IMHO.
Other:
"The Education of Little Tree" by Forrest Carter - an autobiography of a native american growing up in early America.
Ok, that's enough for now.
Some of the classics are old enough now that you can legally download the text in electronic form for free. Also you can check some of the internet sites such as
www.amazon.com that have synopsis and reviews of the books.
- bones