Since Ubuntu 9.04 comes with GNOME 2.26, it inherits its new features. We talked about GNOME 2.26 recently, so let's recap: it comes with the Brasero burning tool, better support for multiple monitors with a new configuration panel, better PulseAudio integration, and so on. This Ubuntu 9.04 beta also comes with X.org 1.6, and several more video cards now use open drivers.
This new release also comes with the new notification system, which we also discussed already on OSNews. The notifications do not have any widgets on them, and therefore cannot be dismissed or clicked in any way - they just disappear. This is how they work:
Other notable improvements are shorter boot times, ext4 support, and a focus on cloud computing.