I didn't like it the first time I saw it (during the original release - I was 19) because I thought the message of the film was essentially: If you keep your hair short and kill people in wars in Indochina, the chances are you'll end up a millionaire. Whereas if you protest against the war, take a walk on the wild side, and sleep around, you'll die of AIDS.
Over the years, I have mellowed considerably and now I love the film a great deal. I'm convinced my initial assessment was wrong, and one of these days I'm going to write an in-depth article to explain why. :)