The Shadow Line just continues to blow me away - literally, this week, with the Glickman/Gatehouse confrontation. Only two episodes left, but we're promised answers this week!
Also, I don't recall if it had a thread of its own or not (and it's not really drama), but I have also bloody loved Psychoville 2. Why they felt the need to move the final episode forward 3 days just for Mock the bloody Week I don't understand, but it was spot on. Okay, the returning character came from nowhere really, but I can buy it.
I'd also like to think the mysterious driver in the car park in PV was Gatehouse