Opposite is a collection of topics on C# and client-side Windows Programming. (Syllabus). This year, I'll increase focus on WPF (Windows Presenation Foundation). The books below do not incorporate WPF but we will use web resources to fill the gaps.

Recommended textbooks:

Pro WPF (Apress) provides very comprehensive coverage of all aspects of WPF. It does not deal with C#.

An excellent book on C# at this level is Joel Murach's book Murach's C# 2008. It is current with developments in .NET 3.5 and works well for those not too confident with C#. Murach's approach is unique presenting topics example by example in a very clear layout. The past version (C# 2005) is equally useful.

Programmers' Heaven free ebook is a first class resource for C#. There are other resources at this site (C# School) that are suited to beginners. Do note that this book however covers only some aspects of .NET 2.0. Beware of this issue since many resources on the web on C# target .NET 1.1 or earlier whereas many new changes in 2.0 render earlier material obsolete.

Developmentor is a training company that provides a good set of tutorials on C# as well as many of the slides you will see on this site. A starting point is their basics slideset.

Corinne Hoisington (of North Carolina) also provides a good selection of material on key C# topics.

Credits

I'd like to acknowledge the support of others in the field who have kindly permitted my linking to their resources.
Stephen Gilbert, Orange Coast College, CA.
Corrinne Hoisington, Cenral Virginia Community College, CA.