I have a friend who just barely keeps her checked bag under 50 lbs. I have another friend who fits everything into her backpack and small rolling bag. Their different styles of packing represent their different styles of travel. My friend who checks her bag is a travel agent and needs to dress professional when leading group cruises. The friend who packs light has no need for that, sometimes traveling alone or with one friend, staying in hostels and eating in the same restaurants locals eat in.
For those travelers that would like to try and travel lighter, I am passing along a recommendation for two web sites that should be a great place to start: OneBag and One Bag One World. Both sites have great recommendations on how to lighten your travel load.