I'm working on moving a client/server application created with C# and WinForms into the SOA/WPF/Silverlight world. One of the big hurdles is the design of the UI. My current UI is MDI driven and users rely heavily on child windows, having many open at the same time and toggling back and forth between them.
What might be the best way to recreate the UI functionality in an MDI-less environment? (I've no desire to create MDI functionality on my own in WPF). Tabs? A list panel that toggles different controls?