Version:            (using KDE KDE 3.5.8)
Installed from:    Ubuntu Packages

I think it would be useful and efficient to have (possibly customizable) 2-line column contents in the message list pane.

What I mean is somethine like this:

====================================
Message # | Column 1 | Column 2    |
====================================
Message 1 | Subject  | Date        |
          | Sender   | Day of week |
------------------------------------
Message 2 | Subject  | Date        |
          | Sender   | Day of week |
------------------------------------

I know this would take up a lot of vertical screen space, but it would also save on a lot of horizontal screen space.

Ideally, some of the lost vertical screen space could be reclaimed by using the date-threading I am suggesting here: http://bugs.kde.org/show_bug.cgi?id=90142