He shot a man in Reno — just to watch him die — and director James Mangold has shot a piece of Johnny Cash's life on film.

"Walk the Line" captures a slice of the legendary country singer's saga. Although it was entertaining, it could've been monumental.

What's good:

It's the story of Cash's early career. Mangold made a wise choice to bookend the film with Cash's 1968 show at Folsom Prison. Cash's performance there is legendary since he connects with his surroundings better than a fish in water.

The man lived a breathtakingly fascinating life and had a singing voice that perfectly reflected his hardened personality. If anyone's life was begging to be made into motion picture it was Cash's.

It would've been impossible to make a movie devoted to the ruggedly weathered man's tale that wasn't riveting. "Walk the Line" never drags and sweats excitement.

What would've made it monumental:

Joaquin Phoenix ("Gladiator") is dead-on for the young Cash look, and captures the aura of the man tremendously well. It's just a shame he sings.

The film would've been great if Cash's voice was used rather than the voice of Phoenix. Films such as "Selena" created a stronger sense of the artist's persona by actually using the musician's singing voice in the movie.

Yes, Phoenix does a semidecent job sounding like Cash, but that's not the point. No one could ever capture the same genuine passion as the Man in Black. He was famous and an inspiration to millions because of his stubbornly distinctive voice. Why try to recreate something that's already perfect?

This film is directed at people somewhat unfamiliar with Cash's career. Big fans of the singer will not be surprised by any of the events in the film, and be forced to dash to their CD players to hear Cash's awe-inspiring voice.