I agree with GoBruins' comments:
My Background:
2.6 undergrad gpa in engineering
ms in engineering completed while working full time
Haas, Anderson - Ding w/o interview
Chi, Duke - Ding w/interview
Darden -Accepted/matriculating
I'd be lying if I said I didn't have one eye on the possibility of my ms helping me get into bschool - but I completed my master's in order to have the degree itself. Getting the ms is probably not the most effective or efficient way to compensate for a low undergrad gpa. Do I get accepted or get interviews without my ms? Probably not. Are there easier/cheaper ways to go about mitigating the ug gpa and achieving the same results - I believe so. Doing well in classes relevant to bschool (stats, econ, etc) would probably help address the academic concerns better than getting an A in mechanics of structural materials - and that's not a gimme.
That all being said, I think that there one aspect (related to bschool) where having an ms is beneficial. My guess is that it will help in recruiting for positions at tech/engineering firms - especially if the job involves interactions with the technical groups.
If the sole reason someone is pursuing a masters is to help them get into an mba program, I would advise them against it.