Looking for ruthless good guys...?

The ones that spring immediately to mind are Jake of the Animorphs, Roy Mustang of Fullmetal Alchemist, Silk of the Belgariad, Vetinari of Discworld, and depending on how far you're willing to stretch the "hero" part, Littlefinger of a Song of Ice and Fire and L of Death Note. They're also common in Westerns and mysteries, though I don't read quite enough in either genre for the non-film names to spring to mind, just Raymond Chandler's detectives and anything that led to a Clint Eastwood character.