Core Data is the most recent article added to Apple's developer connection - the user interface generation is pretty neat: "We've mentioned that you can use Cocoa bindings to connect a Core Data managed object context to your application's user interface. However, early in an application's development life cycle when you are exploring what kinds of objects you need to capture in the data model, you can take advantage of a new feature of Interface Builder that will create prototype interfaces for you. All you need to do is Option-drag an entity from the Xcode Data Model design tool onto a window in Interface Builder and a comprehensive interface will be created for you."
Although think what you could do if the UI and the data used the same data format, like RDF, instead.
Also, spotlight and automator. A review of Tiger fom Supersite for Windows.
And it maybe time to start learning Object-C with things like categories: "Categories allow us to split up a large class into several pieces. Each can be developed and created independently, and then brought together at the end to form the class.
As a consequence however, this allows us some nice advantages. We can, in essence, extend the functionality of any class that may fall into our hands, whether it is in a class you create yourself, or in a binary form, such as in the OPENSTEP/Cocoa/GNUstep frameworks, we can add a category to NSString to provide functionality that the original NSString did not provide. It is possible to even add categories to Object! Categories can also be used to override previous functionality, which allows us then to "patch" these preexisting classes also, which might be provided with a bug."