Another book I think would appeal to this group is Hawksmoor, by Peter Ackroyd. I've read quite a lot of Ackroyd, but this is the one for you guys. It's a supernatural detective story (sort of) intercut between a real 18th century architect who designed quite a lot of churches in London and a modern detective, and it has quite a lot of brutal murders and black arts stuff, as well as some lovely language. I gave it to a smart architect friend once, who was blown away by it. It would be an interesting tourbook for a macabre view of London.
-alga-