Where to Go From Here
Several other useful parts of C# are outside of the scope of this document. To learn these advanced features, consider getting a book on C#. One that I own and recommend is Professional C# 2008 by Christian Nagel, et al. In addition, MSDN is a very good resource, as is Google.
Good resources on LINQ and functional programming
Using functional programming and LINQ can help you write far better code, and be much more productive. There are several excellent resources on learning this. I personally recommend this site: http://blogs.msdn.com/ericwhite/pages/FP-Tutorial.aspx
Using Unsafe code
As you may well be aware, there are several cases when using the automated garbage collector is not what you need. You may also want to use C/C++ style pointers. With C#, you can declare sections of code as unsafe and gain access to these features. To learn how to do this, read http://msdn.microsoft.com/en-us/library/aa288474(VS.71).aspx.
Conclusion
C# is a powerful language that is very feature complete. It provides a level of safety and control that can help developers write very flexible, fast and bug-free code.