As my wife and I are getting a bit older now, we've decided to finally ditch our backpacks in favor of some good wheeled carry-ons. We'd like them though to be both expandable as well as comply with the sometimes tighter size restrictions of smaller international airlines, thus 20"x14"x9". We're willing to pay more for a better bag, assuming it isn't hugely expensive! We'd certainly like to get the best bang for the buck, with as much interior volume/capacity as possible.
Thanks to all that can help!