Along the lines of shows like The Wire, Sons of Anarchy, and Breaking Bad, I highly recommend The Shield.
It's one you have to start at the beginning and watch in order, but it's one of the best TV dramas I've ever seen. It's gritty without being blatantly gratuitous (SOA) and touches on the human element of good people going bad, but more subtly and artfully than Breaking Bad.
The best part, IMO, is that the good guys aren't always good, they don't always escape unscathed, and when they do it's because they did something intelligent, not because of dumb luck like we see all too often in shows and movies.