The first couple of seasons of Arrow are on Netflix now. I've just made it into season two. Good superhero series from the DC Comics universe (Superman/Batman/The Flash) rather than the currently in vogue Marvel Comics universe (Avengers, Iron Man, X-Men, etc.).
The show starts a bit slow when it seems like they have the male lead do a little too much posing and sappy stuff that seems designed to appeal to a young female demographic who they think will watch because he is cute, but it seems like as it goes on it develops into a more serious slightly darker adult action-driven show, and gets a lot better from my entirely subjective perspective. All shows like this have some unrealistic elements by design, but Arrow at least in the parts I have been watching steers clear of supernatural powers and space and that kind of thing, and features a vigilante hero in a world that is mostly realistic as it is portrayed on screen, even though some events seem implausible from time to time. Actor John Barrowman (Captain Jack Harkness from Doctor Who and Torchwood) plays a recurring character on the show.
Netflix also has Marvel's Daredevil, which, while not as good as Arrow, was okay. Daredevil gets a little more unrealistic with a blind guy with special powers fighting crime and stuff like that. Slightly more blood and whatnot involved because it didn't have a first-run on network TV (It's a Netflix original). Overall, I think Arrow is a better show, but if you like those sort of shows, no reason not to give both a try.