74% is average in nearly every commonly accepted grading scale, and would represent a "C" or a "7.5/10" on alternate scales. I thought it best to rate out of a 100-pt scale, so as to more finely differentiate good and bad. If I had to provide a key along with my ratings in this instance, I would say that:

0-15 - Stay away if you value your time in the slightest
16-30 - Watch for free on television if you're busy knitting, or half-asleep
31-50 - Rent if your first pick isn't available
51-65 - Maybe entertaining, seek to rent this first
66-75 - Worthy of a bad theatre experience
76-90 - Pretty good theatre experience, memorable
91-100 - Box office gold, Academy Award, favorite all-time, etc.

The last few movies I've seen were "Lord of War", "Wedding Crashers", "Brokeback Mountain", "A History of Violence", and "Hellboy", and none of them, except perhaps Hellboy, would have cracked the two lower categories. I'm seeing "Walk the Line" tonight, and I'm hoping it's good- it comes highly rated (but then, so did Brokeback...).

I hope you're not serious that the only true litmus test is whether or not Baron Munchausen is considered "beautiful and good". I like kiddie adventure movies (Neverending Story, Star Wars, The Princess Bride, A Knight's Tale), Terry Gilliam, and even the prolific John Neville, but these factors simply didn't combine well enough to make a watchable and/or enjoyable film. So again, let's please see your ratings to better get a sense of your grading style, rather than simply attacking mine.