If there is one consistent thing that I have learned about programming it is that there is always more to know. Being a visual learner, I gravitate towards videos. Here are some excellent videos on Windows Forms Controls, Data Binding and Windows Forms "under the hood":

Visual C# Developer Center : Visual C# How Do I Video Series
WindowsClient.Net : Windows Forms Videos

The videos I found most interesting were:

How to create a System Tray application using the NotifyIcon control
How to call other applications using the Process control
How to use the TreeView control
How to use the WebBrowser control
Databinding Data to User Interface Controls
MSDN Webcast: How Microsoft Technology Works: Windows Forms (Level 200)

Also I must say that I liked the web cast so much that I went to both of Jessica (aka jfo's) Blogs: MSDN, jfo's coding. In particular I found jfo's "Advice to myself, I wish I had had starting out" well worth the read.

Mental note: "must learn WPF".