Samsonite are pretty good. They have good warranties and honour them. Their luggage can be a bit pricey, but it is durable and rugged - all of my suitcases are Samsonite, and they have - quite literally - travelled the globe with me.
I agree with
@Roller; spending money on good quality luggage (especially if you travel a lot) is a must. Not only is it built better and more durable, but it is usually better balanced as well. Re price and Samsonite, I have bought some of my bags during sales, when you can get quite generous discounts. Of course, this means that sometimes you may find yourself buying a suitcase for which you may have no immediate need.
Mandarina Duck also make highly regarded bags and suitcases; I have need actually had one, but I have met those who have used them and rated them highly.
Re airlines and luggage, not surprisingly, they tend to treat business class travellers a lot better.
The other thing to bear in mind is that if you fly with the same carrier all the way through, they tend to be a bit more concerned - and professional - about things such as the safe transport of luggage. In Europe and Asia, I have noticed that difficulties tend to arise when, for whatever reason, a multi-leg journey is undertaken with two or more carriers; their sense of responsibility for your possessions tend to be somewhat reduced when others are also flying you to your destination.