Saw this in the cinema a couple of years ago and it was fantastic fun. A real edge of the seater and the scares worked well on the big screen. Didn't stop me sleeping soundly after but I still recommend it to people who like horror movies.
Have it on dvd now and eventhough my TV is huge and I've a kick ass surround sound set up, it's not as good as in the cinema. That said, it's still well worth a look and much better than any horror I've seen in ages. The director, Neil Marshall's, previous movie was also low budget but no less fun. Dog Soldiers it's called and it's very funny as well as being a nerve shredder. Seek it out!!
And for the record, The Cave was one of the worst 'movies' I've ever seen.