Normally people get stuck with no GUI session because they lack proper VGA drivers setup. Others are stuck at purple screen, but in the end it's the same problem with a touch of plymouth. Wubi dudes get stuck at no grub or grub rescue.
Yet, there seems to be a growing number of cases like this: http://ubuntuforums.org/showthread.php?t=1860359
I have no idea what happened in this cases. Some apparently have no way of using their NIC. Others just don't have fixed/dhcp IP and DNS set. Either way, they seem to not have have all 11.10 packages installed. Those with Internet can't run apt-get update/upgrade, dist-upgrade, do-release-upgrade, etc. Some have lsb_release pointing to 11.04, other 11.10.
Do you have any clue?