I concur with R.J. Sawyer (except, I'm not sure I'd class it as 'science fiction'). It was a very good book. I'll certainly be picking up the second novel - especially if the publisher is paying that much for it *after* reading the full thing!
How about George Alec Effinger's Marîd Audran books (Gravity Fails, et al)?
They've got everything: heavy drug usage, brain implants, James Bond, private detectives, transexuality, and much much more. All set within an interesting cultural setting (Arabian, mainly).