I read the book years ago and it’s one of the few vampire books that has ever freaked me out. I think the movie captured Neville’s loneliness well, but he didn’t have folks outside his door every night like Neville in the book does, which is much more frightening since they call him by name and taunt him.
I agree with the opinions expressed here about the zombies (though they are alive people who are infected) being too strong. I also thought they missed an opportunity to build the story with the alpha male who tracked Neville. I was really interested in how he retained some human intelligence and they didn’t go anywhere with it. Still, I was glad to see the film made and if it gets people to take a look at the book again, that’s even better.