Luther, from the BBC. It's got Idris Elba in it. I didn't really know him before I saw Luther, but now when I see that he's in something, I'm like "Fuck yeah, Idris Elba!" (fingers crossed he gets Bond, but I doubt it'll happen). Anyways, you've heard the premise a million times. A cop who's better at his job than everyone else investigates serial murders. Same old story. Luther doesn't really do something new, it just does the old stuff really, really well. He's a better cop than everyone else, but he's not unbelievably better. He screws up. He thinks of things other people don't... but it's too late. People get hurt because he makes the wrong call. It's an incredibly intense show with some rock-solid acting from the entire cast. It's short, too. Only 14 episodes across 3 seasons. Make sure you have time to watch episodes 5 and 6 together, because you won't want to stop when you get there. Also, the cinematography is fantastic. The whole thing is beautifully shot.
You won't regret it. Or maybe you will - it gets pretty brutal in places. But hopefully not! I haven't seen The Wire, but I've heard good things. It might be a shock to hear him with an English accent, I've heard people say that they didn't realize he wasn't American after watching The Wire.
I liked the Wire a lot. I feel like it portrays the cop world extremely authentically. It starts off slow but it's because they have to introduce the cast of characters and set it up well. At some point they pick up the pace and it gets more complex and interesting from there. And yes, Idris Elba does have a great American accent, but I've seen trailers for Luther and I think I'll manage to get used to his Britishness.