Are you ranking those in terms of importance? If so, I think you've got it backwards. A low score can certainly keep you out, but the GRE is not going to get you in. There are just too many applicants with perfect scores and not enough spots.
I think research and a great
statement of purpose, on the other hand, can tip you over the edge into the admitted pool. Like moomber said, test scores are an easy way to give very quick feedback on your chances. I went to an admissions fair recently, and whenever I asked about the importance of the GMAT/GRE, the admissions rep would ask for my quant score and then say I was in the range of admitted candidates but that the score was not ideal. If I mentioned my research experience and work in applied economics, however, it was like the quant score was forgotten. So if you score on the lower end of the 'acceptable' spectrum, put it in the context of your application as a whole and see whether you've got anything that makes up for it.