The latest set of KDE releases has been announced on Jan 25. It includes major updates to Plasma Workspaces, Applications, and the Development Platform. Version 4.8 provides many new features, as well as improved stability and performance. Read the announcement.

KUbuntu 11.10 user can easily upgrade to KDE 4.8 via ppa:kubuntu-ppa/backports. Just execute following commands in a terminal window and reboot.

sudo apt-add-repository ppa:kubuntu-ppa/backports
sudo apt-get update
sudo apt-get dist-upgrade

Ubuntu 11.10 can also install KDE 4.8 using this ppa, but it’s a bit risky. Be sure you know what you are doing before running following commands 

sudo apt-add-repository ppa:kubuntu-ppa/backports
sudo apt-get update
sudo apt-get install kubuntu-desktop

During the installation, it will ask you choosing display manager, choose KDM if you want to keep KDE. Finally, reboot.