This is the best modern zombie film. If George Romero defined movie zombies for us then Danny Boyle took them to 11 in more brutal and frightening ways. But also in the way the zombies, or rather desperation, bring out our ability to be brutal. Sometimes that’s needed in order to survive, sometimes it’s self-serving.
Our protagonist Jim awakens after being in a coma for a month to find that London is desolate and destroyed. Bleak and stark, the normally bustling streets are uneasily quiet. And soon he discovers why as zombies give chase. Helped by other survivors, his journey then really begins, forging alliances and friendships and having to grieve his own family and then some of his companions as they confront horrible violence.
The rage virus has spread, from one infected person to another through blood contact, usually biting. Though never called zombies, the infected are monstrous shells of former selves, only human in shape, they are violent and bloody fucking fast! These are definitely not the zombies we want to have to deal with in the apocalypse.
Extremely intense from the first, the actors are as skilled as the action. And God did I mention how fucking fast these zombies are? More importantly the relationships develop in a believable way. And it never occurred to me that only processed and irradiated food would survive, nothing fresh, at least not until you can settle and farm, and who knows when that can happen. (Always take notes in survival movies.)
Anyway, in the course of survival, the zombies aren’t the only enemies as they find a blockade that is the source of a signal transmission claiming safe haven. Remember the lesson about things too good to be true? Yeah, these army blockheads have their own wicked agenda, involving rape and some brave new world crap, which the now group of three must escape from. It’s striking to me the empowerment of ordinary people in these situations and the inherent danger of figures of authority. Never trust the Man!
Ultimately, they escape, but not at all easily and the only clear thing is how unclear their fate remains.
Lurking Films 
I have to disagree, I like the movie, but it's not really the best zombie movie, nor a true zombie movie. It's a movie with "infected" -these guys are NOT dead, they run, and vomit blood, they don't eat brains, etc..Best Zombie movie: Dawn of the dead (1978)Check out 28 weeks later; it's pretty good as well