Yet another boxed set query - thrillers this time!

[CarelessWispa]

I know it's been done a thousand times, but this time I'm after something quite specific. I love a good thriller, as does DH. Can you recommend a good boxed set to replace those we've already seen. We've watched (and liked), the following so far:

24 (various series, though got a bit silly towards the end)
Prison Break
Wire (excellent)
Damages
Dexter (less keen)
Spiral
The Killing (best thing on TV last year)
Mad Men (OK, not a thriller, but excellent none-the-less)
Mad Men (ditto)
Murder One

Oh, and I liked Borgen, though DH less keen.

Can anyone recommend anything new that we could try? Don't like science fiction, or vampirey things, but pretty open minded otherwise

Thanks, in advance.

We're watching Spooks at the moment - I'd never seen any of them before. We're on series 5 just now and have really enjoyed it so far. Not exactly a thriller but very good. Series 1- 9 are all around £10 or less on Amazon, the last series is a bit more expensive.