CCK is good stuff. I know that some folks like to design their own modules, and debates rage about the right way to accomplish what CCK accomplishes, but if you've got a drupal site and you want to manage custom content types, CCK is a perfectly respectable option.
Except that it is a pain in the butt. Say you run a small youth program that doubles as a used bike shop. You want to make a custom content type on your future drupal site, for displaying used bikes that you've got in stock. You know the basic fields you need: price, make, model, a photo, what shop it is in, and some room for extra details. To create the CCK content type that contains all of those fields, you need to go through an inane series of forms that'll have you banging your head on the wall if you are the sort of hater who bangs her head on the wall when you're forced to complete a repetative task.
So here is your salvation:
View CCK through the back door