*. Comes with the KDE 4.6 version which brings the Kwin manager (default window handler for KDE).
According to the Kubuntu team, KWin now needs less resources but performs faster than previous versions!. Other benefits include better VGA driver integration, new power management GUI (very impressive and looks gorgeous!) + few improvements to the Dolphin as well (KDE's file manager).
*. File sharing made easy because of Samba!.
Sharing a file or a folder across a network has never been this easy according to Kubuntu team!. Just right click on the file/folder in Dolphin file manager and go to "Properties" and simply, share!.
|Samba ... Samba ... Samba....|
*. Better printer configuration.
Including few bug fixes... the new printer configuration now ingrates better with a lot of printers.
This is a cloud based storage that are hosted directly at KDE servers. Now as a Kubuntu user, you can easily access and manage your OwnCloud easily.
*. Switched to Phonon Gstreamer back-end.
It's a bit sad actually. KDE is certainly not second to no one and from certain aspects... it's way ahead of Gnome too. But for some reason (well, they say it's due to better compatibility with Ubuntu) they've decided to use the Gstreamer (the developers of Gstreamer won't say it's a Gnome project... but they seem to prefer Gnome :) ) as the multimedia framework.
Although the new Phonon... which is the KDE's own impressive multimedia framework, again due to compatibility, Kubuntu will be using Gstreamer via a Phonon back-end. Let's hope that next time they'll give us a full "KDE-lized" desktop.
Anyhow, these are few of the main features of Kubuntu 11.04 Natty Narwhal according to their official release announcement and all the details such as how to download it are also in that page. So follow the link and read it. And if you're upgrading from 10.10 version... then please read this official instruction page before proceeding. Good luck.