Sons of Anarchy. I was introduced to this series by a friend of mine a few years back and to this day, I don't think there's anything on there that can beat it. It's about a biker gang. It contains murder, rape, gun-running, drugs, humour, betrayal and a lot more!
I also really enjoy Person of Interest. It's about a geek who builds an AI surveillance system for the government after the 9/11 terror attack. The system is able to detect attacks that will happen within 24hrs and sorts them into two categories, relevant to terror attacks and non-relevant. The relevant attacks get forwarded to the government and the non-relevant goes to the person who built the system. He couldn't just stand by and watch people die so he hires an ex-agent of the CIA who intervenes in these situations.