My field tends to be flooded with applicants, so some schools automatically trash the bottom XX% of applications according to GPA/GRE, because they don't have resources to evaluate 500 full applications. So I'd say GPA/GRE are definitely important because you need relatively high scores to even get your foot in the door.
Again, speaking for my discipline, I think resume/experience is very important, followed by LORs, then transcripts, then SOP. They seem to care more about the grammar/structure of the SOP, rather than the content. The exception would be if you have unusually low scores or something else that you explain in the essay, in which case it could be quite influential!