My newly installed Slackware running KDE, with calendar, clock, gmail
and news widgets.

You can find more about Conky and how to install it at:

http://www.go2linux.org/conky-system-monitor-for-linux

Now, if you really want to make it look great, something like this:

You may want to install Conky Launchpad.

Download link and instructions are:

http://gnome-look.org/content/show.php/Conky+Launchpad?content=134620

URL:  http://www.howtoforge.com/the-perfect-desktop-linux-min...

From the "The Perfect ..." series, we now have Linux Mint Debian Edition as "The perfect Desktop".