Ahh, a fellow foreign flick fan. Agree on Infernal Affairs trilogy and Girl with the Dragon Tattoo trilogy. Judging by those picks and your being a GSP fan, I would have to recommend the South Korean vengeance trilogy-”Oldboy”, “Sympathy for Mr. Vengeance”, and “Sympathy for Lady Vengeance”.
Have seem all of them as hollywood stopped making entertaining movies have been watching mostly Asian movies...
Check out Vengeance by johnie To and the good the bad and the weird a Chinese tribute to Sergio Leone