We got the AllerEase Ultimate pillowcase for my son who has an allergy to dust mites. I absolutely love the cotton material this is made from. It hardly makes a sound as you readjust. I remember when I was a kid we had the noisy plastic ones that crinkled with every breath you took. Welcome to the future my friends! This pillowcase is it!!  
The zipper is very sturdy and I can definitely see this lasting the entire life of the pillow.  The material also allows for air movement which is wonderful because the last thing you want is to have a pillowcase that makes your face sweat while you sleep. Good quality product for not a lot of money.