Saw this at Wadcutter, so I thought I'd see which ones I've read.  I don't give much weight to these lists.  There are lots of books that I would probably put on such a list that other people wouldn't agree with, and I certainly don't agree with some of the books included here.

Phobos Entertainment - Top 100 SF Books
2. Foundation Written by Isaac Asimov (entire series, I think)
3. Dune Written by Frank Herbert (entire series, not including anything written by his son after his death)
4. Man in the High Castle Written by Philip K. Dick (sorry RAH fans, but Philip K. Dick is the Master)
6. Valis Written by Philip K. Dick (the trilogy)
7. Frankenstein Written by Mary Wollstonecraft Shelley
11. Cuckoo’s Egg Written by C.J. Cherryh
15. 2001: A Space Odyssey Written by Arthur C. Clarke
16. Ringworld Written by Larry Niven (and the sequel)
17. A Case of Conscience Written by James Blish
21. More Than Human Written by Theodore Sturgeon
27. The War of the Worlds Written by H.G. Wells
28. 20,000 Leagues Under the Sea Written by Jules Verne
30. The Time Machine Written by H.G. Wells
33. Neuromancer Written by William Gibson
38. Dragonflight Written by Anne McCaffrey (whole series)
39. Journey to the Center of the Earth Written by Jules Verne
40. Stranger in a Strange Land Written by Robert Heinlein
43. Blood Music Written by Greg Bear
46. I, Robot Written by Isaac Asimov
49. Brave New World Written by Aldous Huxley
51. 1984 Written by George Orwell
52. The Strange Case of Dr. Jeckyl And Mr. Hyde Written by Robert Louis Stevenson
57. Startide Rising Written by David Brin (also Sundiver--which was the first book in this series--Startide is the second)
60. A Clockwork Orange Written by Anthony Burgess
61. Fahrenheit 451 Written by Ray Bradbury
68. Flatland Written by Edwin Abbot
70. Dragon’s Egg Written by Robert L. Forward (also the sequel)
79. The Martian Chronicles Written by Ray Bradbury
84. Alice in Wonderland Written by Lewis Carroll (and Through the Looking-Glass)
85. Hitchhiker’s Guide to the Galaxy Written by Douglas Adams (whole series)
91. I Am Legend Written by Richard Matheson

Only 31.  But then I've read lots of things not on the list.

Others that I would probably put on this list:
The Amber Series by Roger Zelazny
The Illuminatus! Trilogy by Robert Anton Wilson
The Four Lords of the Diamond series by Jack L. Chalker
The Spellsinger series by Alan Dean Foster

Just kidding!  Heh heh.  That last one was just a sort of in-joke with one of the readers here. You know who you are.  But I'm serious about the other three.

I noticed that A.E.Van Vogt has a book on this list.  I read a book by this author once.  Unfortunately I no longer remember the title.  I considered it the biggest waste of time I had ever spent reading a book.  I was so disgusted with it that I didn't even take it back to the used book store to trade for another book.  I just threw it in the trash.

There are several authors on this list who I have read books written by, just not the specific book mentioned.  Saberhagen, Simak, and Cherryh come to mind.

Writing this up has made me think it's way past time to re-read my Theodore Sturgeon collection.  And I'll probably have more comments in the vein in a later post.