The WinForms FolderBrowserDialog is a bit clunky:
Yes, it will do exactly as it says - let the user browse a tree of folders, and select one. Unfortunately, it doesn't allow the user to navigate very quickly, type (or paste) a path in themselves, or jump to any of the 'library' or 'quick access' folders. It has the look-and-feel of the old Windows XP style folder browser dialog, regardless of which OS the user is using.
Windows Vista and onwards introduced a better dialog (one that most users will be more familiar with), but you can't use it in WinForms out of the box.
Luckily, Sven Groot (aka Ookii) has put together a nice open source project called Ookii.Dialogs that includes a .NET wrapper of the Vista-style FolderBrowserDialog and can be used as a drop-in replacement for the traditional FolderBrowserDialog (and will even render as such when running on Windows XP). Update/Edit: As of 2018, the project is now maintained by C. Augusto Proiete on GitHub (WPF / WinForms)
This gives us the much nicer folder browser dialog:
Ookii.Dialogs also includes a number of other useful dialogs: