For me, Moulin Rouge falls into the category of being a tremendously enjoyable movie... but one that I have absolutely no intention of rewatching (intentionally, I mean, I'll happily watch the odd five minutes here & there if I hop across it on TV). It's extremely stylised, which automatically polarise audiences, but I liked its style. You can put it the same "over-stylised" category as 300, Sin City, Pulp Fiction, Matrix, Hulk, or Batman Returns (moreso than Batman & Robin, I'd actually say). You'll tend make your mind up about whether you like these movies pretty quickly because they're all so in your face with their style choices.
I enjoyed the Moulin Rouge ride a lot, but it felt like a one-trick pony in that respect; I didn't find anything deeper to entice me to watch it again. Whereas some of the other stylised movies I mentioned above I do enjoy rewatching for reasons other than the style.
FWIW, just to run through his other movies, I loved the first 10 minutes of Romeo+Juliet; it showed real inventiveness in modernising the setting & props. But I thought the rest of the movie was a massive missed opportunity. And Strictly Ballroom is the polar opposite of what I enjoy in a movie. Haven't seen Australia but from what I've heard, I think I might like it. I'm not hopeful for The Great Gatsby but maybe I'll be surprised.