Xubuntu 12.04 is a brand-new version of the popular Ubuntu flavour featuring the Xfce 4.8 desktop. Xubuntu 12.04 is a Long-Term Support release (LTS) and will be supported for three years per the Xubuntu LTS plan. Release notes: the i386 images use a non-PAE kernel, the non-PAE kernel will not be available in future Xubuntu releases; some default shortcuts have been changed, added and deleted; pavucontrol is used instead of xfce4-mixer due to latter not supporting PulseAudio; the Alacarte menu editor is installed by default and will work with Xfce-related menu items as well; lots of appearance improvements, including new branding.
Xubuntu is a Linux distribution based on Ubuntu. Unlike its parent, however, Xubuntu uses the light-weight Xfce desktop environment and is optimised for lower-end machines. The distribution includes only GTK+ applications where possible.