In fact there have been four earlier film versions of The Great Gatsby, with Baz Luhrman's being the fifth, as well as an opera and some stage adaptations. The first was a 1920s silent film which has now been lost, and the most recent apart from Luhrman's was a made for TV movie in 2000 starring Toby Stephens. There was also a 1949 version with Alan Ladd.
However, the most famous adaptation was the 1974 film, directed by Jack Clayton from a script by Francis Ford Coppola and starring Robert Redford and Mia Farrow. This was a hit and most comparisons with the newest movie have been based on that. The 1974 film was felt by many critics and audiences to be closer to the story and ideas of Scott Fitzgerald's novel. However, many felt that it lacked feeling and didn't bring the era - the 1920s - to life, while the new film does convey the colour and glamour of that age. Some feel though, that it goes too far in this direction and doesn't convey any of Fitzerald's irony - you can see a review with this opinion here.