I didn't make it through "Angels and Demons" yet. I keep putting it down.
I couldn't put down "The Da Vinci Code". It just had all the elements I like.
Back when I was writing shareware programs, I used to protect them with my own encryption routines. I learned that stuff on my own. It was funny to me how many things in the book lined up with conclusions I had drawn for myself doing home grown cryptography. This would include the belief that if anyone was smart enough to break my code, that they earned the secret within (a free, fully functioning copy of my program).
I didn't get caught up in the religious aspects of the book, I just enjoyed it on a coding level. I guess most people wouldn't see it that way at all.