Flat or roll

As I frantically pack everything we own into 5 suitcases(now I know this all fit a month ago!)the eternal dilemma...do you roll the clothes to make them as small as possible, or lay them flat? Bridget is the packing connoisseur in our family and has done some amazing things with our stuff, but right now we have both systems going. Tonight will be the weigh in... so far, it seems you CAN fit more with rolling...BUT it may weight too much and thus be rejected by the airline. I will report in on this so you too can end this debate in your house! OK, maybe our house is just a whole lot weirder than others...I'm willing to believe that :)