Camera cases are very personal things. Everyone will have different preferences and different things will be important to them when transporting and carrying their camera. There are lots of things to take into account and it might even be the case that you will want more than one camera case, depending on how you use all of your photography equipment.
First of all, think about how much equipment you have and how much of it you would want with you at any one time. You can get cases that will accommodate various different pieces of equipment, such as additional lenses and filters. However, if you have lots of lenses, you may want to buy individual cases for them.
If you travel with your camera, protection will be the most important consideration for you. Make sure your case is well padded and will offer you lots of protection for your camera.