I really like the All-in-One window feature of Xcode 2.  It has quickly become my favorite windowing mode.  The big thing that I wish it did is “contextual” toolbars in the project view that are dependent on the type of file being edited.  That way I can have the add entity, add relationship, and add attribute items in the toolbar when I’m editing a model but not when I’m editing code.  Like wise, I’d like to have the new breakpoint item when editing code, but not when I’m editing a model.  Looks like it’s time for another feature request bug report.