Lately people were asking me, what is the minimal list of things expected when you are looking for a WPF programmer. So, I managed to compile a list, hope this helps

1) XAML Basics & Basic controls such as TextBox, Buttons etc.,
2) VisualTree and LogicalTree
3) Bubbling and Tunneling

4) DependencyProperty
5) AttachedProperty

6) DataTemplate
7) ControlTemplate

8) Style

9) DataBinding

Triggers:
10) EventTriggers
11) DataTriggers

MVVM Basics & Commands:
12) DelegateCommand
13) RelayCommand
14) ApplicationCommands
15) RoutedEvent
16) RoutedCommand

Transformations:
17) RenderTransform
18) LayoutTransform

Resources:
19) BinaryResource
20) LogicalResource
21) StaticResource
22) DynamicResource
23) RelativeResource

Panles and Basic Controls:
24) Layouts and Panels
25) UserControl
26) ContentControl
27) Some Controls like Grid, TreeView and Charts

Interfaces and Collections:
28) IValueConverter
29) INotifyPropertyChanged
30) ObservableCollection
31) CollectionViewSource

Tools:
Knowledge on IDE/Tools such as Expression Blend, Expression Designer and Visual Studio will be of great advantage.