The book I'm most thankful for is Pride and Prejudice by Jane Austen. I will admit, I saw the Jennifer Ehle miniseries first, but it inspired me to read the source material. I find something new every time I read the book or watch one of the movie versions (even the horrid 1940's move with screenplay credit to Aldous Huxly that takes place in the Civil War-era South).
I love Mr. Bennet's humor and Miss Bingley's scheming. I've had long discussions over how exactly Lady Catherine received her gossip and if Mary would have been happy with Mr. Collins.
My favorite quote is from Miss Bingley about Elizabeth, "To walk three miles, or four miles, or five miles, or whatever it is, above her ankles in dirt, and alone, quite alone! ... It seems to me to show an abominable sort of conceited independence,"