One of the things that’s a bit annoying with Expression Blend is that when you go to reference an assembly you get the standard Windows file open dialog. That is;

raises the dialog;

and that’s not what you see in Visual Studio and makes hunting down the assemblies that you want a little more “tricky”. What I tend to do is to use a Windows 7 library to add all the locations for my typical assemblies and then it makes it relatively easy to find what I want – at the time of writing mine looks like this;

and so when I’m hunting for the charting library from the toolkit I just need to bang in a search string;

and it’s pretty quick to locate it.