Judy and I went to see this one yesterday, and we both enjoyed it immensely. Usually Judy's not too fond of the movies I choose, so I was glad to hit on one she liked.
The plot's pretty simple. The English government has become oppressive. The people have sacrificed freedom for security. The man known only as V wants to take the government down, so he sets about doing it. He's a terrorist, a revolutionary, or a freedom fighter, I guess, depending on your point of view. Or maybe he's an anarchist. Mainly, though, he just wants revenge (you'll have to see the movie to find out why; I'm not telling). He doesn't have any plans to replace the current government with something better. I can't remember the exact line from the movie, but when he's asked about that he says something like, "There are no certainties, only opportunities."
Hugo Weaving is V, and he plays the entire movie behind an immobile mask of Guy Fawkes. I thought he did an amazing job of conveying the character's thoughts and feelings with his voice and body language. In fact, I found him so convincing that a couple of times I almost thought the mask changed expression.
Natalie Portman plays a woman named Evey, who goes from conforming to the norm to informing on V even though he's rescued her, to helping him. I'd say she redeems herself for the various Star Wars prequels here.
The whole cast is good, and so is the script, which is more literate and less action-oriented than you might have been led to believe by the trailers. Check it out.