Ubuntu Distros
Xubuntu is an official derivative of Ubuntu using the Xfce desktop environment. It is intended for users with less-powerful computers, or those that require a highly efficient desktop environment on faster systems. Xubuntu features primarily GNOME applications. Xubuntu Vs Ubuntu, it won't make a huge difference, but you may see things performing slightly better under xubuntu due to the smaller resources XFCE should use compared to Gnome/KDE.
 Ubuntu Netbook Remix (UNR)
Ubuntu Netbook Remix is optimized to run on a new category of affordable Internet-centric devices called netbooks. It includes a new consumer-friendly interface that allows users to quickly and easily get on-line and use their favorite applications. A remix is a 'respun' version of Ubuntu built for a specific purpose.
 Ubuntu 10.04 "Lucid"
 Building Ubuntu Distros
 Xubuntu 9.10 "Karmic Koala"
Command to build the basic Karmic (9.10) xfce4 image for OMAPZoom:
sudo ./rootstock --fqdn OMAPZoom --login ubuntu --password pwd --imagesize 2G --dist karmic \ --serial ttyS3 --seed xfce4,gdm,xubuntu-gdm-theme,xubuntu-artwork
Upon Completion, it creates the Root file System - armel-rootfs-<date>.tgz
 UNR 9.10 "Karmic Koala"
To use Ubuntu-netbook-remix, you can change the seed name in the rootstock command line to ubuntu-netbook-remix.
The command to build UNR Karmic is:
sudo ./rootstock --fqdn OMAPZoom --login ubuntu --password pwd --imagesize 3G --dist karmic \ --serial ttyS3 --seed ubuntu-netbook-remix,ubuntu-netbook-remix-default-settings
Note: Keep the login user name as "ubuntu" as it is the system user with root privileges