In chronological order, except for Standard Book of Spells, because I had to conserve bullet points. 100 in total, and I would read every single one of them. (With the exception of Tom's Diary, of course.)
  1. The Standard Book Of Spells
    Grades 1, 2, 3, 4, 5, and 6.
  2. A History of Magic
  3. Magical Theory
  4. A Beginner's Guide to Transfiguration
  5. One Thousand Magical Herbs and Fungi
  6. Magical Drafts and Potions
  7. Fantastic Beasts and Where to Find Them
  8. The Dark Forces: A Guide to Self-Protection
  9. Modern Magical History
  10. The Rise and Fall of the Dark Arts
  11. Great Wizarding Events of the Twentieth Century
  12. Quidditch Through the Ages
  13. Notable Magical Names of Our Time
  14. Important Magical Discoveries
  15. A Study of Recent Developments in Wizardry
  16. Dragon-Breeding for Pleasure and Profit
  17. Dragon Species of Great Britain and Ireland
  18. From Egg to Inferno, A Dragon Keeper's Guide
  19. Charm Your Own Cheese
  20. Enchantment in Baking
  21. One Minute Feasts—It's Magic!
  22. Gilderoy Lockhart's Guide to Household Pests
  23. The Adventures of Martin Miggs, the Mad Muggle
    Technically a comic book, I believe.
  24. Break with a Banshee
  25. Gadding with Ghouls
  26. Holidays with Hags
  27. Travels with Trolls
  28. Voyages with Vampires
  29. Wanderings with Werewolves
  30. Year with the Yeti
  31. Prefects Who Gained Power
  32. Magical Me
  33. Encyclopedia of Toadstools
  34. Hogwarts, A History
  35. Moste Potente Potions
  36. Flying with the Cannons
  37. Sonnets of a Sorcerer
  38. The Diary of T.M. Riddle
  39. Ancient Runes Made Easy
  40. Handbook of Do-It-Yourself Broomcare
  41. The Monster Book of Monsters
  42. Invisible Book of Invisibility
  43. Unfogging the Future
  44. Predicting the Unpredictable: Insulate Yourself Against Shocks
  45. Broken Balls: When Fortunes Turn Foul
  46. Death Omens: What to Do When You Know the Worst Is Coming
  47. Intermediate Transfiguration
  48. Sites of Historical Sorcery
  49. Which Broomstick
  50. Home Life and Social Habits of British Muggles
  51. The Handbook of Hippogriff Psychology
  52. Fowl or Foul? A Study of Hippogriff brutality
  53. Numerology and Gramatica
  54. Common Magical Ailments and Afflictions
  55. An Appraisal of Magical Education in Europe
  56. Magical Water Plants of the Mediterranean
  57. Men Who Love Dragons Too Much
  58. Basic Hexes for the Busy and Vexed
  59. A Guide to Advanced Transfiguration
  60. Quidditch Teams of Britain and Ireland
  61. Olde and Forgotten Bewitchments and Charms
  62. Saucy Tricks for Tricky Sorts
  63. Weird Wizarding Dilemmas and Their Solutions
  64. Madcap Magic for Wacky Warlocks
  65. A Guide to Medieval Sorcery
  66. An Anthology of Eighteenth-Century Charms
  67. Dreadful Denizens of the Deep
  68. Powers You Never Knew You Had and What to Do with Them Now You've Wised Up
  69. Where There's a Wand, There's a Way
  70. Nature's Nobility: A Wizarding Genealogy
  71. Defensive Magical Theory
  72. The Dream Oracle
  73. Asiatic Anti-Venoms
  74. A Compendium of Common Curses and Their Counter-Actions
  75. The Dark Arts Outsmarted
  76. Self-Defensive Spellwork
  77. Jinxes for the Jinxed
  78. Practical Defensive Magic and Its Use Against the Dark Arts
  79. New Theory of Numerology
  80. Magical Hieroglyphs and Logograms
  81. Spellman's Syllabary
  82. Achievements in Charming
  83. The Healer's Helpmate
  84. Advanced Rune Translation
  85. Confronting the Faceless
  86. Advanced Potion-Making
  87. Flesh-Eating Tress of the World
  88. Quintessence: A Quest
  89. Blood Brothers: My Life Amongst the Vampires
  90. Magick Moste Evile
  91. The Life and Lies of Albus Dumbledore
  92. Secrets of the Darkest Arts
  93. Twelve Fail-Safe Ways to Charm Witches
  94. The Tales of Beedle the Bard
  95. Armando Dippet: Master or Moron?