If you haven't yet, I highly suggest everyone read A Madness of Angels and The Midnight Mayor, the only books in the Matthew Swift series by Kate Griffin.  They are a fun read, and I have to say, though I love Butcher and the Dresden Files, the magic use in Griffin's universe is brilliant and more to my tastes, and would be easy to simulate using the Fate system.  Even if you don't play in her world, I think you'll be surprised how much information there is to mine from these books, particularly if you are going to play in and around London, or really any other large city.

Seriously, check them out...you won't be disappointed.