I had thought for a long time that something from Halliburton would be about the best it gets as far as hard luggage goes, but apparently that may not be the case. I knew nothing about them however an article about a plane that was inspired by the luggage because the luggage was inspired by the plane caught my attention.
I fly all the time for work (Weekly). Not a fan of Rimowa except for carry-on. They cases are very thin lightweight aluminum that are very easily damaged.
Tip: Don't buy Rimowa locally, there is a store called Koffer Direkt or some such on the internet that will ship it to you from Germany at much better prices... better still, just buy it in Germany if you are passing through. You can get the VAT refunded on the way out. Search the travel Products forum over on FlyerTalk for more info.