I read the Halo books too, but they were nothing special. Just back story for fans. 
I've read so many books, but now that I think about it, I don't remember most of 'em anymore. I remember one semester in middle school I read so many AR books that I had like 156 points. Then I stopped reading AR books and still ended up #3 for the most points at the end of the year. When I want to read something, I will friggin' read it. 
To add to the book list... 
The Merlin saga and Heartlight, T.A. Barron (definitely a young-adult series though) 
Jurassic Park and the Lost World, Michael Crichton 
The Dungeon series, Jose Philip Farmer  
*looks up AP reading lists* 
Cry, the Beloved Country- Alan Paton (see the movie with James Earl Jones) 
Count of Monte Cristo- Alexander Dumas 
Frankenstein- Mary Shelley 
Grendle- John Gardener 
The Good Earth- Pearl S. Buck 
The Grapes of Wrath 
The Old Man and the Sea- Ernest Hemmingway 
The Pearl- 
The Iliad and the Odyssey- Homer 
The Scarlet Letter- Nathaniel Hawthorne 
Z for Zacharia- Robert C. O'Brian 
Animal Farm- George Orwell 
Gulliver's Travels- Johnathan Swift 
And then there were None- and other Agatha Christie novels 
One Flew Over the Kuckoo's Nest- Ken Kesey 
Books definitely not on the list: 
A tale of two cities 
Heart of Darkness 
The Blind Assassin 
The House on Mango Street 
The Great Gatsby 
Huckleberry Finn 
Anything Shakespeare. 'cept maybe Macbeth. 
Brave New World 
I remember reading the secret of nimh. I just don't remember any of the content.