I think Death in 5 Boxes is excellent - I liked all those crypto-criminals. It's almost like a textbook for budding arsonists and cat burglars. This was the first time I'd come across the method, so I thought it was brilliant. The murderer also really surprised me, and I kicked myself for forgetting about dragons. In fact, I think it's a lot better than The Judas Window, which has a really clever twist halfway through, but an arbitrary murderer and a boring method.
Nick Fuller.