The Lies of Locke Lamora by Scott Lynch. I could have used this book on about half of this book a day list I think, but have tried to hold back so as not to totally bore everyone silly.
Not only was it a Book Spa recommended book by my favourite bookseller in Bath, recently I was in Heffers, the biggest bookshop in Cambridge and two of Lynch's Gentlemen Bastards books published so far are Top Staff Picks… Lies and the third book Republic of Thieves. In case you needed any more convincing.
A TIP: For those who read it for the first time, Lynch spends a good deal of time building Locke's world. Stick with the first 150 pages and it will be worth it!