I'd say GPA matters a bit more. I graduated with a good GPA. While I also had great general GRE scores, my physics subject score was rather atrocious (about 45%-ile). Yet I recently got admission to an MS program. So I'm guessing that GPA is a bit more important than the GRE.
This isn't to say that the GRE isn't important. If you get low grades but do very well on the GRE, it can compensate for your GPA. Ohio State, for example, will consider applicants who fall below the 3.0 minimum, provided that they submit GRE subject scores. I have a friend who's got a 2.4 physics GPA, but who got a 75%-ile on his physics GRE, so such a thing is possible.
Anyway, I've got no expert knowledge on this subject; like you I'm just a grad school applicant. But this is what I've learned from my experiences thus far.