Definitely at consulting firms, the first screen (because its easiest) is marks and GMAT,
unless you've done something really really cool that grabs the consulting reading your package. As a result, you need to figure out if you're a 'vanilla consultant' and need to pass the first screen based on marks and GMAT, or if you're someone whose done something really, really cool in your life, that you can describe.
If you're getting an interview at H/S/W with a sub 700 score, then you've got something that makes you non-vanilla.
Don't retake the GMAT - focus all your efforts on knowing yourself to have an awesome interview. I think that once you're at the interview stage at HBS, your application is less important.
I know
many, many analysts from the top 3 consulting firms who wrote the GMAT and ditdn't get 730. I also believe that McK/BCG/Bain are looking for really inspiring people to help with the consultant diversity irrespective of the GMAT.
Case in point: McKinsey two years ago designated a partner who was a priest, and had no formal business training.
And please, don't edit my posts and substatively change the meaning of what I'm trying to say. mNeo, you took out the critical content that I was trying to convey.