How can I retrieve the system icon associated with a file/folder so that I can show it in the list view adjacent to the file/folder name?
See Obtaining (and managing) file and folder icons using SHGetFileInfo in C#.
You need to use Icon.ExtractAssociatedIcon
Icon icon = Icon.ExtractAssociatedIcon(filepath);
Take a look at Icon.ExtractAssociatedIcon documentation
Note: this works only for files. For folders you need P/Invoke sample is here Edit: Page is now defunct, please refer to this copy on the Wayback Machine.