I love using Xcode debugger. You can any time take a look at the variable's values, you can even change them.
The problem rises when u are testing images, and here pops up the question:
Can I somehow DISPLAY the image that is referenced by the image variable? I know i can see raw bytes of it, but it would be much more human friendly if that would pop a window with its contents.
Xcode might not support it. Maybe there is an external tool that would help with that?