I will chime in with a specific example.
In speaking with an ex admissions director at an ultra elite, I mentioned my GMAT score. His response "Good, you needed it" - with reference to my GPA of 3.0 being less than sufficient.
My friend, who spoke with the same individual, mentioned his GMAT score of 680. The ex director told him flatly "Not good enough with your GPA. You should retake or possibly take some quantitive at large courses prior to applying." His GPA was, admittely, a bit worse at 2.5.
The point I'm making here is that you have to weigh your GMAT against the rest of your application. In my case I knew I needed a 700+ score to offset a weak undergrad GPA.
If you have a 3.8 undergrad GPA, 5 years experience, are already a manager, have a diverse set of activities under your belt, etc etc etc - then a 650 may be sufficient. If, on the other hand, you lack in ANY of these areas, a 650 may not be considered sufficient.
Remember: A 650 wont keep you out and a 750 wont get you in.