If you've read the book of I Am Legend the film is a bit lame. Especially the ending and the changes to the monsters. In the book they're much more like regular vampires. It was an alright film, but I'd rather it have not been attributed to the book. Although then people would complain that it was derivative.
And 28 Days Later is fantastic. 28 Weeks... not so much. I think it suffered from a higher budget, if anything. Made it too reliant on the special effects rather than the rawness of the first film.
There are 10 types of people in the world: Those who understand binary and those who don't.