I've spoken with a TON of 1st and 2nd year business students about this over the last few months (Wanted to know if my high GMAT would help me if I decided to go to a school outside the M7). The consensus is, the GMAT helps you get a first round interview, but doesn't help too much after that. A lot of people think 700 is the cut off, but I met a 680 GMAT person from Duke this weekend who got Mckinsey (Full disclosure: she was a URM Female though). Likewise, I spoke to a guy who said he had a low GMAT (not sure the exact score), who got BCG LA offer from UCLA (He had front office banking experience).
Seems GMAT is one of many ways to help you stand out, but far from the only way...but if you don't have a high GMAT, you need to have SOME WAY to stand out (e.g. networking, leadership, prior WE). Interested in hearing more perspectives though.