Boo Boo

Ok, I know that this is a wierd question, but... am becoming increasing aware of the enforcement of the 55lb per bag weight limit (on a recent flight, the lovely check-in lady at UA - we were flying First Class and she was having trouble chekcing us in. - let us off the excess...). Is there a good suitcase size (assuming average packing habits) to help minimise the chances of exceeding this limit whilst maximising what I can take with me?

Our suitcases are well travelled and getting the worse for wear (one of the handles snapped etc.) and we are beginning to look at changing them. Our current cases are HUGE (26"x18"x10") and expandable. Like many good young women, I manage to pack to my limits: so the bigger the case, probably the more I pack!

Also, there is no easy way to weigh our cases before we get to the airport.

So I am thinking the best way to reduce the risk of going over the weight limit is to - this time round - buy smaller suitcases. I appreciate that the weight of a suitcase depends on what you put in it (i.e. a case of concrete bricks will weigh more than the same case full of feather pillows!), but is there - in anyone's experience - a good suitcase size for the 55lbs limit? (obviously a TINY suitcase would do this, but I want a good compromise...)

Thanks,
Boo