When Should I Use The Interface Builder?-Collection of common programming errors

As I’m learning the iPhone API, the book I’m using has me doing everything possible with the Interface Builder. We (lonely here sometimes) are writing code, too, but I really feel like I’m getting to know the Interface Builder quite well.

I know that the Interface Builder is different from other GUI Builders as it uses serialized objects and doesn’t write code. This is supposedly a good thing. So…in day-to-day work, is it the tool of choice, or should I try to get over my dependence on the Interface Builder?

Also: if you suggest that “it depends on what you’re doing,” what does it depend on? How should I make the decision to use the Interface Builder or not?

Note: The subjective and argumentative version of this question was titled, Interface Builder: Serious Tool or Just For Kids? but I decided against it since I want to avoid getting the question closed.