I found this list online many years ago. I’m sure it’s far from exhaustive, outdated, and my buddy reddy will have some choice criticisms on it, but it does cover a great range of the “classics” in sci-fi/fantasy and really is a good guide to get started if you’re so inclined.

I’ve bolded the ones I’ve finished already.

100 Books Thou Shalt Read Before You Die
By the Inquest Staff

1. Lord of the Rings by J.R.R. Tolkien

2. The Chronicles of Amber by Roger Zelazny (First 5 books, although all ten are now available in an Omnibus)
- read the first book

3. The Ender Quartet by Orson Scott Card (Personal note: I loved the First book, hated the last three)
– read the first 3…will never read another Orson Scott Card book again tho, he’s on my ban list due to his homophobic attitude.

4. Neuromancer by William Gibson

5. The Chronicles of Thomas Covenant the Unbeliever by Stephen R. Donaldson (6 Books total)

6. Foundation by Isaac Asimov (6 Books total)

7. Dune by Frank Herbert (Just the first book)

8. Elric by Michael Moorcock (available in omnibus editions)

9. The Man in the High Castle by Phillip K. Dick

10. 1984 by George Orwell

11. Hyperion by Dan Simmons (four books)

12. The Stars My Destination by Alfred Bester

13. Tigana by Guy Gavriel Kay

14. Frankenstein by Mary Shelley

15. Do Androids Dream of Electric Sheep? by Phillip K. Dick (also called Bladerunner)

16. The Sword of Shannara by Terry Brooks

17. The Anubis Gates by Tim Powers

18. Lightning by Dean Koontz

19. The Uplift Trilogy by David Brin

20. Ringworld by Larry Niven

21. The Time Machine by H.G. Wells

22. Fafhrd and the Gray Mouser by Fritz Leiber (complete series)

23. A Princess of Mars by Edgar Rice Burroughs

24. The Hitchhiker’s Guide to the Galaxy

25. The Stand by Stephen King

26. Le Morte d’Arthur by Sir Thomas Mallory

27. I, Robot by Isaac Asimov

28. The Moon is a Harsh Mistress by Robert Heinlein

29. Watership Down by Richard Adams

30. Fahrenheit 451 by Ray Bradbury

31. The Hobbit by J.R.R. Tolkien

32. Helliconia by Brain Aldiss (three books)

33. The Book of the New Sun by Gene Wolfe (five books)

34. Gulliver’s Travels by Jonathon Swift

35. Mindkiller by Spider Robinson (novella in book Deathkiller)

36. Blood Music by Greg Bear

37. The Green Mile by Stephen King

38. Interview with the Vampire by Anne Rice

39. Starship Troopers by Robert Heinlein

40. The Chronicles of Narnia by C.S. Lewis (seven books)

41. The Illuminatus! Trilogy by Robert Shea and Robert Anton Wilson

42. Watchers by Dean Koontz

43. The Demolished Man by Alfred Bester

44. Emphyrio by Jack Vance

45. The Wizard of Oz by Frank L. Baum (first book only)

46. War of the Worlds by H.G. Wells

47. Mythago Wood by Robert Holdstock

48. Animal Farm by George Orwell

49. The Princess Bride by William Goldman

50. Wheel of Time by Robert Jordan (complete series)
– only read first 3 books…god this series goes on and on and on and…

51. It by Stephen King

52. A Clockwork Orange by Anthony Burgess

53. Timescape by Gregory Benford

54. Pern by Anne McCaffery (complete series)

55. Slaughterhouse Five by Kurt Vonnegut

56. Good Omens by Neil Gaiman and Terry Pratchett

57. Fionavar by Guy Gavriel Kay (three books)

58. Earthsea “trilogy” by Ursula K. LeGuin

59. 2001 by Arthur C. Clarke (four books)

60. Xenogenesis by Octavia Butler (three books)

61. A Fire Upon the Deep by Vernor Vinge

62. Conan by Robert E. Howard

63. Mars trilogy by Kim Stanley Robinson

64. Midnight at the Well of Souls by Jack L. Chalker

65. A Spell for Chameleon by Piers Anthoy
– I loved most of the Xanth novels as a kid…

66. The Gap by Stephen R. Donaldson (five books)

67. A Connecticut Yankee in King Arthur’s Court by Mark Twain

68. Adventures of the Stainless Steel Rat by Harry Harrison

69. The Martian Chronicles by Ray Bradbury

70. Dark Elf series by R. A. Salvatore

71. West of Eden by Harry Harrison

72. A Fine and Private Place by Peter S. Beagle

73. 20,000 Leagues Under the Sea by Jules Verne

74. Dying Inside by Robert Silverberg

75. Dragonlance by Margaret Weis and Tracy Hickman

76. Lensman by E.E. “Doc” Smith (six books)

77. Something Wicked This Way Comes by Ray Bradbury

78. The Mote in God’s Eye by Larry Niven and Jerry Pournelle

79. Stranger in a Strange Land by Robert Heinlein

80. Space Trilogy by C.S. Lewis (First Book: Out of the Silent Planet)

81. The Invisible Man by H.G. Wells

82. Gun, With Occasional Music by Jonathan Lethem

83. Lyonesse by Jack Vance (three books)

84. Catspaw by Joan Vinge

85. Crystal Express by Bruce Stirling

86. The Last Unicorn by Peter S. Beagle

87. To Your Scattered Bodies Go by Phillip Jose Farmer

88. The Silence of the Lambs by Thomas Harris

89. Downbelow Station by C.J. Cherryh

90. Flowers for Algernon by Daniel Keyes

91. The Songs of Distant Earth by Arthur C. Clarke

92. “The Four Lords of the Diamond” by Jack Chalker (four books)

93. Swords by Fred Saberhagen (more than ten books, first book: An Armory of Swords)

94. Way Station by Clifford Simak

95. The Kraken Wakes by John Wydham

96. Snow Crash by Neal Stephenson

97. The High Crusade by Paul Anderson

98. Through the Looking Glass by Lewis Carroll

99. Carrion Comfort by Dan Simmons

100. The Postman by David Brin