First post - just listing the 100 books and will count my tally tomorrow. This list is from 2003 though so I wonder what amazing books from the last 2 decades might now be added if it was to be redone!
1. The Lord of the Rings, JRR Tolkien 2. Pride and Prejudice, Jane Austen 3. His Dark Materials, Philip Pullman 4. The Hitchhiker's Guide to the Galaxy, Douglas Adams 5. Harry Potter and the Goblet of Fire, JK Rowling 6. To Kill a Mockingbird, Harper Lee 7. Winnie the Pooh, AA Milne 8. Nineteen Eighty-Four, George Orwell 9. The Lion, the Witch and the Wardrobe, CS Lewis 10. Jane Eyre, Charlotte Brontë 11. Catch-22, Joseph Heller 12. Wuthering Heights, Emily Brontë 13. Birdsong, Sebastian Faulks 14. Rebecca, Daphne du Maurier 15. The Catcher in the Rye, JD Salinger 16. The Wind in the Willows, Kenneth Grahame 17. Great Expectations, Charles Dickens 18. Little Women, Louisa May Alcott 19. Captain Corelli's Mandolin, Louis de Bernieres 20. War and Peace, Leo Tolstoy 21. Gone with the Wind, Margaret Mitchell 22. Harry Potter And The Philosopher's Stone, JK Rowling 23. Harry Potter And The Chamber Of Secrets, JK Rowling 24. Harry Potter And The Prisoner Of Azkaban, JK Rowling 25. The Hobbit, JRR Tolkien 26. Tess Of The D'Urbervilles, Thomas Hardy 27. Middlemarch, George Eliot 28. A Prayer For Owen Meany, John Irving 29. The Grapes Of Wrath, John Steinbeck 30. Alice's Adventures In Wonderland, Lewis Carroll 31. The Story Of Tracy Beaker, Jacqueline Wilson 32. One Hundred Years Of Solitude, Gabriel García Márquez 33. The Pillars Of The Earth, Ken Follett 34. David Copperfield, Charles Dickens 35. Charlie And The Chocolate Factory, Roald Dahl 36. Treasure Island, Robert Louis Stevenson 37. A Town Like Alice, Nevil Shute 38. Persuasion, Jane Austen 39. Dune, Frank Herbert 40. Emma, Jane Austen 41. Anne Of Green Gables, LM Montgomery 42. Watership Down, Richard Adams 43. The Great Gatsby, F Scott Fitzgerald 44. The Count Of Monte Cristo, Alexandre Dumas 45. Brideshead Revisited, Evelyn Waugh 46. Animal Farm, George Orwell 47. A Christmas Carol, Charles Dickens 48. Far From The Madding Crowd, Thomas Hardy 49. Goodnight Mister Tom, Michelle Magorian 50. The Shell Seekers, Rosamunde Pilcher 51. The Secret Garden, Frances Hodgson Burnett 52. Of Mice And Men, John Steinbeck 53. The Stand, Stephen King 54. Anna Karenina, Leo Tolstoy 55. A Suitable Boy, Vikram Seth 56. The BFG, Roald Dahl 57. Swallows And Amazons, Arthur Ransome 58. Black Beauty, Anna Sewell 59. Artemis Fowl, Eoin Colfer 60. Crime And Punishment, Fyodor Dostoyevsky 61. Noughts And Crosses, Malorie Blackman 62. Memoirs Of A Geisha, Arthur Golden 63. A Tale Of Two Cities, Charles Dickens 64. The Thorn Birds, Colleen McCollough 65. Mort, Terry Pratchett 66. The Magic Faraway Tree, Enid Blyton 67. The Magus, John Fowles 68. Good Omens, Terry Pratchett and Neil Gaiman 69. Guards! Guards!, Terry Pratchett 70. Lord Of The Flies, William Golding 71. Perfume, Patrick Süskind 72. The Ragged Trousered Philanthropists, Robert Tressell 73. Night Watch, Terry Pratchett 74. Matilda, Roald Dahl 75. Bridget Jones's Diary, Helen Fielding 76. The Secret History, Donna Tartt 77. The Woman In White, Wilkie Collins 78. Ulysses, James Joyce 79. Bleak House, Charles Dickens 80. Double Act, Jacqueline Wilson 81. The Twits, Roald Dahl 82. I Capture The Castle, Dodie Smith 83. Holes, Louis Sachar 84. Gormenghast, Mervyn Peake 85. The God Of Small Things, Arundhati Roy 86. Vicky Angel, Jacqueline Wilson 87. Brave New World, Aldous Huxley 88. Cold Comfort Farm, Stella Gibbons 89. Magician, Raymond E Feist 90. On The Road, Jack Kerouac 91. The Godfather, Mario Puzo 92. The Clan Of The Cave Bear, Jean M Auel 93. The Colour Of Magic, Terry Pratchett 94. The Alchemist, Paulo Coelho 95. Katherine, Anya Seton 96. Kane And Abel, Jeffrey Archer 97. Love In The Time Of Cholera, Gabriel García Márquez 98. Girls In Love, Jacqueline Wilson 99. The Princess Diaries, Meg Cabot 100. Midnight's Children, Salman Rushdie
1. The Lord of the Rings, JRR Tolkien
2. Pride and Prejudice, Jane Austen
3. His Dark Materials, Philip Pullman
4. The Hitchhiker's Guide to the Galaxy, Douglas Adams
5. Harry Potter and the Goblet of Fire, JK Rowling
6. To Kill a Mockingbird, Harper Lee
7. Winnie the Pooh, AA Milne
8. Nineteen Eighty-Four, George Orwell
9. The Lion, the Witch and the Wardrobe, CS Lewis
10. Jane Eyre, Charlotte Brontë
11. Catch-22, Joseph Heller
12. Wuthering Heights, Emily Brontë
13. Birdsong, Sebastian Faulks
14. Rebecca, Daphne du Maurier
15. The Catcher in the Rye, JD Salinger
16. The Wind in the Willows, Kenneth Grahame
17. Great Expectations, Charles Dickens
18. Little Women, Louisa May Alcott
19. Captain Corelli's Mandolin, Louis de Bernieres
20. War and Peace, Leo Tolstoy
21. Gone with the Wind, Margaret Mitchell
22. Harry Potter And The Philosopher's Stone, JK Rowling
23. Harry Potter And The Chamber Of Secrets, JK Rowling
24. Harry Potter And The Prisoner Of Azkaban, JK Rowling
25. The Hobbit, JRR Tolkien
26. Tess Of The D'Urbervilles, Thomas Hardy
27. Middlemarch, George Eliot
28. A Prayer For Owen Meany, John Irving
29. The Grapes Of Wrath, John Steinbeck
30. Alice's Adventures In Wonderland, Lewis Carroll
31. The Story Of Tracy Beaker, Jacqueline Wilson
32. One Hundred Years Of Solitude, Gabriel García Márquez
33. The Pillars Of The Earth, Ken Follett
34. David Copperfield, Charles Dickens
35. Charlie And The Chocolate Factory, Roald Dahl
36. Treasure Island, Robert Louis Stevenson
37. A Town Like Alice, Nevil Shute
38. Persuasion, Jane Austen
39. Dune, Frank Herbert
40. Emma, Jane Austen
41. Anne Of Green Gables, LM Montgomery
42. Watership Down, Richard Adams
43. The Great Gatsby, F Scott Fitzgerald
44. The Count Of Monte Cristo, Alexandre Dumas
45. Brideshead Revisited, Evelyn Waugh
46. Animal Farm, George Orwell
47. A Christmas Carol, Charles Dickens
48. Far From The Madding Crowd, Thomas Hardy
49. Goodnight Mister Tom, Michelle Magorian
50. The Shell Seekers, Rosamunde Pilcher
51. The Secret Garden, Frances Hodgson Burnett
52. Of Mice And Men, John Steinbeck
53. The Stand, Stephen King
54. Anna Karenina, Leo Tolstoy
55. A Suitable Boy, Vikram Seth
56. The BFG, Roald Dahl
57. Swallows And Amazons, Arthur Ransome
58. Black Beauty, Anna Sewell
59. Artemis Fowl, Eoin Colfer
60. Crime And Punishment, Fyodor Dostoyevsky
61. Noughts And Crosses, Malorie Blackman
62. Memoirs Of A Geisha, Arthur Golden
63. A Tale Of Two Cities, Charles Dickens
64. The Thorn Birds, Colleen McCollough
65. Mort, Terry Pratchett
66. The Magic Faraway Tree, Enid Blyton
67. The Magus, John Fowles
68. Good Omens, Terry Pratchett and Neil Gaiman
69. Guards! Guards!, Terry Pratchett
70. Lord Of The Flies, William Golding
71. Perfume, Patrick Süskind
72. The Ragged Trousered Philanthropists, Robert Tressell
73. Night Watch, Terry Pratchett
74. Matilda, Roald Dahl
75. Bridget Jones's Diary, Helen Fielding
76. The Secret History, Donna Tartt
77. The Woman In White, Wilkie Collins
78. Ulysses, James Joyce
79. Bleak House, Charles Dickens
80. Double Act, Jacqueline Wilson
81. The Twits, Roald Dahl
82. I Capture The Castle, Dodie Smith
83. Holes, Louis Sachar
84. Gormenghast, Mervyn Peake
85. The God Of Small Things, Arundhati Roy
86. Vicky Angel, Jacqueline Wilson
87. Brave New World, Aldous Huxley
88. Cold Comfort Farm, Stella Gibbons
89. Magician, Raymond E Feist
90. On The Road, Jack Kerouac
91. The Godfather, Mario Puzo
92. The Clan Of The Cave Bear, Jean M Auel
93. The Colour Of Magic, Terry Pratchett
94. The Alchemist, Paulo Coelho
95. Katherine, Anya Seton
96. Kane And Abel, Jeffrey Archer
97. Love In The Time Of Cholera, Gabriel García Márquez
98. Girls In Love, Jacqueline Wilson
99. The Princess Diaries, Meg Cabot
100. Midnight's Children, Salman Rushdie