I can save two hours of your life: 8Mile is the exact same movie as The Karate Kid.
Eminem is Daniel LaRusso. Mekhi Phifer is Mr. Miyagi. Brittany Murphy is Ali Mills (the love interest). And all the mean Detroit rappers are the Cobra Kai's.
The movie comes to climax as the reluctant warrior (Daniel-San/Eminem) battles at a open-mic "tournament." Just when you thought your wounded hero was down for the count he delivers a crushing blow that defeats the evil bully rappers.
This movie isn't horrible - but it ain't great either. Curtis Hanson did a much better job on LA Confidential.