The 1933 version is my favorite...I have seen it a hundred times over the decades, it's a fond part of my childhood. The 2005 Jackson version comes in a close second. It's a beautiful film with fantastic effects, but it's hard to beat your first love. The '76 film has some moments, and Rick Baker is great in the suit....but it lacks something.
I also recommend 1986's KING KONG LIVES (the sequel to '76 KONG with Linda Hamilton) it's goofy fun, not to be taken seriously, but not as outrageous as 1967's KING KONG ESCAPES.