What are the very best books for book clubs to read?

Our library just got a grant. The librarian has asked my help in choosing book sets for book clubs. We'll get 5-10 copies of one book along with discussion questions. Since I have a book club, she asked me to help choose the books. We'll only get about 10-15 titles, so I need books that appeal to lots of people with most if not all having less than 500 pages. I'm not looking for a link with thousands of book club titles. I'd like to hear what your reading group has enjoyed the most ;)