Not that it really matters to the story, but I would define the series like this: it is a murder mystery with definite non-mainstream hacker culture mixed in, very cyberpunk aware, but wrapped in a film-noir style.
The important part being that the story is deeply layered, with the initial mystery acting as the catalyst to a whole set of new problems, each one pulling Garamond more and more out of his depth.
Ghost in the Shell, I think. But with less violence. This is a more pensive series.
Not making any sense, am I?