I have this in my DVD collection and I think it is a good film, I am really not into zombie type films.
But with a virtually unknown cast and a minuscule budget this film has done good. Being a British film think it does not seem to translate well outside of Britain, like alot of British fims/television some people just don't understand the dark humour and satire.
For me the creepiest part of the whole film was the deserted streets of London, for anyone who has ever been to any of the landmarks will know that it is crowded at the best of times and to see it completely deserted is unnerving.
In closing my film synopsis is this, essentially, 28 Days Later is a treatise on man's inherently violent nature and a meditation on the myth of a civilised society ... with zombies