I have been working with a lot of really good people at Microsoft and we have come up with a poster that lists the important namespaces and classes in .NET Framework 4.

You can download the PDF version of the poster from http://download.microsoft.com/download/E/6/A/E6A8A715-7695-493C-8CFA-8E0C23A4BE1D/098-115952-NETFX4-Poster.pdf

If you have a plotter or a printer that can handle 24” x 36” paper you will have a good looking poster. If not you can print it and do the cut and tape the printed pages together. If you are attending PDC we are planning on having copies of the poster available there.