Binary package hint: ubiquity
When installing from ubiquity, if you're connected to a lan using a wired connection, without connection to the internet, apt-get stalls because it cannot find the repositories. This is visible in /var/log/messages, but this is completely invisible to the average user. Once you unplug the network cable, ubiquity complains about security repositories not being available, and install finishes without any problems. Even if you manually edit /etc/apt/sources.list before starting install, it won't help, because ubiquity updates the repository list before updating apt. The result is that a new user thinks the install has stalled (and in a way, it actually has, since it seems to be an infinite loop) and will give up.
It is worth noting that I was installing to sdb, having sdb1 as an ntfs windows xp partition.
Thank you for your bug report.
To allow us to fix this bug, we need more informations. Please, could you tell us what version of Ubuntu are you using, and what kind of image you loaded (Desktop, Alternate, 386, amd64, ecc)? Also, can you confirm you have checked md5sum and verifyed CD after burning?