Mark Strong is brilliant in everything he does, but this is probably his best work ever. A story told in four parts from four different points of view (one of which is Game of Thrones star Lena Headey's), The Long Firm is a character study of Harry Stark. He's a charismatic, complex, and totally fascinating London gangster. The show is set in the '60s, so as well as amazing performances, you also get some killer costumes.
Buy it on Amazon now.