I am not a fan of KDE or Gnome since both have become too heavy for the kind of machines I use but I try when something new comes up. I had tried KDE 4.0 last year and wrote about the Desktop Widgets.
Since KDE 4.2 is having many new features i decided to install it. I have Ubuntu 8.04 on this machine but KDE 4.2 is not available for this version. I decided to install Kubuntu 8.10 for a change. After installation I applied all the updates. Then added the following repository:
deb http://ppa.launchpad.net/kubuntu-experimental/ubuntu intrepid main
and the package signing key through the command:
gpg --keyserver keyserver.ubuntu.com --recv-keys 493B3065 && gpg --export -a 493B3065 | sudo apt-key add -
Then updated through Adept Updater tool in the system tray.
After reboot it was KDE 4.2.
Some people don't like the application launcher of KDE 4 for them the old launcher has been added as a widget called traditional menu based launcher. There are many widgets and I have added Analog clock, CPU Temperature, weather, Twitter and Calculator and you can see them on the screenshot below:
In addition the KDE Window Manager has Desktop effects like COMPIZ and you can see the cube below: