Since the thread has already been hijacked, I'm going to add my two cents...
Pride and Prejudice is my all-time favorite novel. We won't talk about the recent movie [[shudder]], but the A&E miniseries does the book justice.
I too hesitated on the Twilight series, thinking that they were "teen fiction," but, as my fellow DIS Twigirls and Twiguys know, I am now a huge fan. Not "great literature," by any stretch, but very good reads with interesting characters and quite a unique storyline.
My other long-time favorite is "The Mists of Avalon." If you like historical fiction and are a fan of the Arthurian legend, you must read this novel - written from the perspective of the WOMEN in the story.
Like Kevin, I loved Pillars of the Earth.
Finally, I am currently working my way back through Gabaldon's "Outlander" series. Time travel has always intrigued me and these books are a rare combination of romance, a little science fiction (the time travel part), and accurate historical references. You get a history lesson with a dose of Jamie Fraser thrown in! What more could you ask for?