The Prefect is big, smart, and fun -- and really has everything you'd want in a speculative fiction novel. The novel begins with Prefect Dreyfus (Prefects are like detectives) investigating the recent destruction of a habitat. The investigation ultimately leads Dreyfus to information of a takeover plot from a hostile AI that threatens the entire collection of habitats in the system.
Buttressing the drama of the main plot is Reynolds' fascinating imagining of a 25th Century society of thousands of orbital habitats and evolved technology.
Note: The Prefect is set in the Revelation Space universe but as near as I can tell (without having read all the other books), it's completely standalone.