I have heard that the bar is higher for international students: American professors don't know as much about your education system, so they don't know to interpret grades and need to lean on a test score more. This might be different if you're coming from Oxford or something.
This spring, I had a UCLA grad student tell me that while the website says they expect an average successful applicant to have about an 80%, the real cutoff is 60%. (As in, if your score is below 80% you can still get in with other strong points, while if it's below 60% they don't read the application.) He said this at lunch with a professor who was on the admissions committee, although said professor didn't say anything in response, so take that as you will.
I got into Berkeley with a 76%, but I have no idea what my classmates' scores were. I strongly suspect that while GRE scores above 80% are nice, they are not at all a defining factor.
Also, in defense of Berkeley: the department doesn't feel at all cutthroat. Of course, I may feel very different when I'm actually a PhD candidate...