Roots by Alex Haley: This is another epic story that is worth reading more than once.
The Red Tent by Anita Diamant: I loved this book so much. I'm a sucker for birth and sisterhood-of-women stuff.
Life of Pi by Yann Martel: Amazing, amazing read. A far-fetched, but still somehow believable story.
She's Come Undone by Wally Lamb: I've read this one twice and loved it even more the second time. I love a good story of dysfunction.
Running With Scissors by Augusten Burroughs: Another memoir about complete and utter dysfunction, but told without an ounce of self-pity and loads of sarcasm and humor. Right up my alley. People seem to either hate this book or love it. I loved it, in fact so much that I immediately went out and bought and read all of his other books.
Dry by Augusten Burroughs: A follow-up to Running With Scissors, this is his account of dealing with his alcoholism and drug addiction.
Blackbird by Jennifer Lauck: Another memoir about a really effed-up childhood.
The Poisonwood Bible by Barbara Kingsolver: Really good book; appealed to my atheist sensibilities.
The Kite Runner by Khaled Hosseini: Wonderful story.
A Thousand Splendid Suns by Khaled Hosseini: Even better than his first book in my opinion.
Island of the Blue Dolphins by Scott O'Dell: I loved this book as much as an adult as I did as a kid . . . and it made me cry just as much.
I'm sure there are more, but there's my starter list.