Looking at a couple of
points charts from dvcmember.com, I'd say a 2 bedroom and a 1 bedroom would probably work best. A GV sleeps 12, but that's usually just 6 beds - 1 in the master bedroom, 2 in another bedroom, 2 in a third bedroom and another bed in the living area sofa. (There's probably a resort that has some different layout, but the point is the same - if you have adults and/or kids who can't or won't share a bed, you're apt to have problems.) I checked 4 resorts and, with the exception of OKW, a 1 bedroom plus a 2 bedroom was cheaper in terms of points than a Grand Villa.
A 2 bedroom gives you the bed in the master bedroom that can be 'closed' for privacy, plus the studio that can be 'closed' for privacy. Put kids in the sofa bed of the main room and, if necessary, you still have the sofa bed in the studio portion. The 1 bedroom then gives you, again, that master bedroom and sofa bed in the living area. If you tell Disney that you're traveling together, they'll try to get the two rooms close to one another.
Obviously, depending on ages and family relations, the GV might work out just fine for you. With no details other than what you've given, though, I hesitate to say that it's the best solution. And the cost difference is going to be dependent on the resort you want to stay at.