Joey's words are absolutely correct and what I was getting at. If your grades and undergraduate institution are sh!t, then you will not even get into a second-tier school, no matter how well you score on this test. Conversely, if you have good grades (3.9-4.0) in mathematics, went to a decent school, and have research experience, then even a middling GRE score (50th-60th percentile) will be sufficient to get into a solid if not excellent program.
The GRE is across the board the most grossly overrated factor of one's application. Let this be a warning to posterity.