For me it has to be Agents of SHIELD, I've been watching it from the start and it got a lot more interesting once SHIELD collapsed. It also retains that slightly tongue in cheek approach that is such a big part of the marvel films, which I really like. Plus it's one of the few action series with a large number of capable female characters in it.

The only other series I'm watching is Gotham (the rest are all on channels I don't get), and while it's fairly good I think it suffers a lot from DC's 'no more jokes' approach. Having such a brutal and unpleasant setting without any humour to occasionally lighten the mood gets rather depressing.