Take the Reavers from Firefly/Serenity, add a little Resident Evil and Blade, and you have I Am Legend, which me and my friend went and saw last night.
The idea is that humans tried to make a genetically altered virus to cure cancer, and it became a plague that kills most people, and turns the rest into violent, hyper-aggressive, light sensitive, flesh eating zombie/vampire things.
Will Smith plays a guy who thinks he's the last living uninfected human on earth, having a natural immunity to the virus. By day he hunts deer, gathers supplies, looks for other survivors, and works on a cure for the virus. By night he locks himself in a fortress so the infected can't find him.
The movie does a pretty good job of showing the effects of isolation on a human... Will talks to maniquins as if they're living people and has lengthly conversations with his dog. Eventually he starts going crazy. The only negative was that the monsters were all CG and they didn't look entirely real. If they can make Gollum look solid, why do they often fuck up in other movies?
It had it's slow, quiet moments, it's moments of Will's character going fruity, it had scary horror moments, and it had moments with Will running around with machine guns killing the zombie people. It was a good movie.
It wasn't faithful to the book though... if you want faithful, stick with the original movie, The Last Man On Earth.