The wire aside, I think Idris Elba is bad
Loved him in The Wire and was genuinely surprised to find out he was English.
By yeah, in everything else he does that awful, forced, drawn out speech style that I can't really describe well (I can do a great impression of it though). Gordon Ramsey speaks in a similar way if that helps. Pretty wank.
Lot of people manic actors who aren't in the slightest but rates as actors too.
I'd say Nicolas Cage but he's pretty much a joke anyway, so hardly overrated.