Marvel's Iron Man 2 may have disappointed those hoping for the biggest US opening weekend ever, but with the fifth largest opening in history, I'd hope that no-one's too upset. Wondering which movies were more immediately successful? The list is under the jump, along with other reasons for Marvel and Paramount to be happy about Tony Stark's latest flight.

IM2's estimated $133.6 million opening might not have beaten The Dark Knight's $158.4 million as some had been predicting - It was the widest open in US cinema history, after all - but it not only handily built on the success of the first Iron Man movie (which made $98.6 million on opening) but also gave distributor Paramount its most successful opening first weekend ever.

Interestingly enough, the four movies to have had bigger opening weekends are all also sequels: Pirates Of The Caribbean: Dead Man's Chest, The Twilight Saga: New Moon, Spider-Man 3 and the previously-mentioned Dark Knight. Clearly, the way to have a really successful movie is to already have made a really successful movie.