Gran Torino might not have that much action, as far as gunplay and explosions, but there's a lot of tension and menace. Clint Eastwood is a serious hardass, and it's easy to buy his over-the-top portrayal of a racist, grizzled Korean War vet. There's a suprising amount of humor, often coming from the "Did he just say that?" angle. The best stuff comes from the ways he tries to teach his wuss of a neighbor how to act like a man.
The movie takes its time but never feels like it's dragging. Its biggest weakness is the sub-par acting of the supporting cast, and it's obvious that Eastwood hired amateur actors to play his Hmong neighbors to have them feel more authentic. The brother and sister are piss poor at acting, but good at portraying obnoxious Asian stereotypes. The only authenticity I'll give them is that I felt like I was living next to Tech's campus again.
It all leads to a logical, yet surprising conclusion which really sends the movie into Very Good territory. If you're wary of Hollywood ramming a "lesson learned" sermon down your throat regarding Eastwood's character, rest easy. It never patronizes us by forcing us to believe this crusty bastard suddenly decides to stop using racial slurs and being distrustful of others. The change we get is natural and welcome.