Outside of the general, or cliched themes (science verses faith, dedication verses obsession, public verses private, and past verses present) presented in Dan Brown's novel Angels and Demons, one could justify that another theme of the novel is self-actualization.
Throughout the novel, readers see many of the character depicted in the novel struggling with inner demons. The fact that Robert Langdon, Vittoria Vetra, and Carlo Ventresca all try to sort out their place in the world (one in which they are caught between their religious ideology (or lack of religious ideology) and the problems facing the Vatican.
Both Langdon and Vittoria are forced to come to grips with their own personal thoughts on religion and their scientific minds may conflict with getting done what needs to be done (saving the Vatican). Carlo Ventresca, at the end of the novel, cannot bear his own sins and commits suicide.
Basically, each of the "main" characters involved must come to terms with who they are, how their actions have impacted the world, and what they must do to make up for their "sins." It is their search to find their greatest potential in both life and the situation which lead them to their own personal actualization. Each character, at one point or another, comes to question their actions based upon what is happening around them. It is, therefore, justifiable to discern that a non-cliched theme of the novel is self-actualization.