Read the "usage directions" too! Rated 4 out of 5 stars
Great to navigate quickly. Don't forget to read the usage directions in the Addons->Options of Nostalgy, I discovered there it can even do more, like: quickly switch focus between the folders, threads and message panes, scroll the message without switching focus away from the threads pane, switch to "cc" and "bcc" in message composition.
Dreams for the future (aka request for featuritis to get the last point and make me go from 9 to 10): incorporate "ThreadKey" and "Maximize Message Pane" functionality, use eg. Shift-G to see only a list of folders with unread mail (and a count?), Esc-V for access to the view box? ;-)