The first consideration when thinking about luggage is where are you going and how often you travel. If you travel a lot, buying a cheap bag or luggage is not the way to go. Cheap luggage can work if you travel maybe once or twice a year, but, as with anything, cheap luggage has its drawbacks. For instance, with cheap luggage, if the baggage handlers throw it around, will it hold up? Also, one thing many people do not consider is, is your luggage water proof? Do you know, if not, you had better consider it. There is nothing worse than seeing your luggage on the tarmac, getting soaking wet, right before a 10 hour flight to Africa. 10 hours for your clothes and personal effects to grow mold and be ruined when you get there. If you do not know if your luggage is water proof, at least pack your clothes in clean plastic garbage bags. Then if your luggage does get wet, your things at least will stay dry.
If you travel a lot, do not consider cheap luggage, it simply will not stand up to all the punishment luggage gets. Go for something of quality and a good brand like Samsonite. Make sure it is soft material, that is water proof, good body construction, large 2.5 inch wheels and I suggest a leather handle, not a telescopic handle. The reason is a telescopic handle can bend, and if it bends and or breaks, well you will be carry your bag through LAX. Go for a detachable leather handle that you can pack and when you arrive to your destination, simply pull it out and go.
Another consideration for luggage many people do not think about is the size and weight. Your carry on cannot be more than 50 pounds on most airlines and should be soft not hard shell. I you are going to travel to an exotic island, on smaller planes, weight restrictions will probably be more strict. Thus find out what they are before you travel. And if you have to check in your carry on, does it have your video camera and other valuables. As I said before, make sure you plan your trip, do not allow your trip to make your plans. Consider where you are going, what planes you will be taking and you will have a happy trip. Forget about planning and you will be spending a lot more money on buying new things because you forgot about your luggage.
If you are wondering, there are lots of place online to buy. Just spend some time exploring the various sites and look for end of the year sales. Also, make sure they offer free shipping and a no questions return policy, and buy quality, it will help you in the end.