I have been fixated on "Gatsby" for many years. I have seen three of the four filmed versions, and am desperate to see the long-thought-lost 1926 silent version. Apparently others have sought out this missing classic, too, with no luck. (A tantalizing glimpse of the silent "Gatsby" exists in the form of the movie's original trailer. The only version actually filmed in the correct time period, it seems to really capture the era. Apparently, contemporary reviews disagree.)
Which actor was best at portraying Jay Gatsby? It's hard to tell, not being able to see Warner Baxter in the 1926 version. Alan Ladd (1949) seems too rough on the edges, clearly telegraphing his supposedly-mysterious past; Toby Stephens (2000) was too, I don't know, too British, or something.
The best portrayal was Robert Redford (1974) in what has to be the definitive version: It has the right look (costumes, sets, locations), music (Nelson Riddle) and the correct -- what, ennui? -- that define the people and the time.
If you have never read "The Great Gatsby" you really are missing something amazing.
If you have a copy of the 1926 silent version, please let me know. Really.