The WPF animation capabilities are powerful, but a bit opaque. EID helps, although in its current pre-beta state it only unlocks so much of the system. Animation begs for more abstraction and it was only a matter of time before someone did it. Check out Brandon Furwangler's Animation Behaviors. He has a long post on the forums about it including a pretty comprehensive code sample. The gist of it is the ability to add the following kinds of syntax to any FrameworkElement:
<Rectangle my:AnimationBehaviorHost.LoadedBehavior="SlideInFromTop" my:AnimationBehaviorHost.ClickBehavior="Jiggle" my:AnimationBehaviorHost.UnloadedBehavior="SlideOutToBottom" Width="200" Height="100" Fill="red" />Nice! I look forward to seeing where Brandon -- and the community at large -- takes this. He's looking for contributors and help.