Lightweight Hardside Luggage - Luggage & Bags - Tumi
I'm surprised no one has mentioned Tumi.
I may be a little out of touch, most of my travel was years ago. I flew weekly for years and this was the only luggage that stood up to the beating. I still have one of the soft side Kevlar carry-on bags like the flight attendants use. It's 20+ yrs old and still works perfectly.
The old style has a couple of features the new ones don't due to update security concerns, but if I were to buy another, it would be Tumi.
I linked the hard sides above, but they carry a full line of soft side as well. You can buy on-line or in most of the better travel stores.
I have the old style of this one:
Frequent Traveler Zippered Expandable Carry-On - Tumi
I can easily pack a weeks worth of clothes in it, carry it on or check it.