1. Lord of the Rings - Tolkien
2 The Last Unicorn -Beagle
3 The Odyssey - Homer
4 Siddhartha - Hesse
5 Green Mansions - Hudson
6 Stranger in a Strange Land - Heinlein
7 The Once and Future King - White
8 The Lathe of Heaven - Leguin
9 Dune - Herbert
10 The Dream Quest of Unknown Kadeth - Lovecraft
11 Mila 18 - Uris
12 Dracula - Stoker
13 Ender's Game - Orson Scot Card
14 Volkhavaar - Tanith Lee
15 The Cornelius Chronicles - Michael Morecock
It is rather biased to SF and Fantasy, I admit...But these are books whose images pop into my head from time to time.