Are you waiting to read Dan Brown’s The Lost Symbol?
If you liked the Da Vinci code try one of these titles:

The Last Cato By Matilde Asensi
The Alexandria Link By Steve Berry
The Da Vinci Cod: A Fishy Parody By Don Brine
The Rule of Four By Ian Caldwell
The Geographer's Library By Jon Fasman
The Assassini By Thomas Gifford
Ex-Libris By Ross King
The Testament By Eric Van Lustbader
The Book of Fate By Brad Meltzer
Labyrinth By Kate Mosse