As others have already mentioned some of these, but...
Dexter (which I read is coming back next year, and I really hope it makes up for the quite lame ending!),
The Bridge - the original and the best in Scandi Noir, IMO! I think this would be the series I wish I'd not already seen so I could watch it again. Every time I see it's back on iPlayer it makes me so envious of the people watching it for the first time 😁
Green wing, which was one of the funnier comedies I'd seen, particularly the utterly ridiculous last ep of s1, and for some reason, first ep, where she's just started at the hospital and she's pulling along her case but with the handle down. That bit always has me laughing!
The IT Crowd was good; fav episode where he was 'leg disabled'! (I'm disabled and found it hilarious so I hope I'm not offending anyone else by this!)
There's bound to be more, mostly dramas as, actually, I don't generally watch comedies. I suppose Grey's Anatomy. Might have become less good as it's gone on, but I still really look forward to a new series (Sky, s17, I'm looking at you...I'm waiting to watch it on nowtv but have heard not available here until April, even though it's already started in the US. I quite like the spin off Starion 19 as well.
I loved Bones and The Mentalist. In the 'olden days', before my son left home those were the two main ones we'd sit and watch together each week when the new eps came out.
Similar, but different ('Patrick Jane' being in it), was The Guardian. Loved that. Think it was pre-Bones
Going back even further in time would have been Twin Peaks! I had to watch that every week., or at least video it if I was going out. You couldn't risk missing an episode, it was confusing and weird enough that even watching every single bit of it you were still left feeling a bit 'wtf was that?!' 😁
This Life also, if anyone remembers that?
Our Friends In The North, that too was great!