I'm actually in 2 book clubs irl, long story which unfortunately does NOT involve me being a quick reader! For one of them I just finished Mudbound by Hillary Jordan and I LOVED THIS BOOK. The discussion isn't for a week and a half so I can't say that we had a great discussion, but there's plenty to discuss in the book. It also won the 2006 Bellwether Prize if that sways you.
Some other suggestions that I have enjoyed the discussions are :
The Catcher in the Rye by J.D. Salinger
The Corrections by Jonathan Franzen
Isaac's Storm by Erik Larson
Eat, Pray, Love by Elizabeth Gilbert
The Curious Incident of the Dog in the Night Time by Mark Haddon
Blindness by Jose Saramago
The Glass Castle by Jeanette Walls
Anna Karenina by Leo Tolstory (over December break for 2 months)
The Book Thief by Markus Zusak
The Guernsey Literary and Potato Peel Pie Society by Mary Ann Shaffer and Annie Barrows
It seems that most book clubs read the same books, which does help people who despite all sense are in 2 book clubs, but hopefully you haven't read all of these yet. It's always tough to make the selection. I was surprised by the over all success of The Catcher in the Rye, my last pick. It was a good discussion. Good Luck!