There's a kind of two-step process to installing Ubuntu Linux on a system: running through the actual installation, then booting into the desktop and waiting for a huge load of updates to download. Use a Minimal image instead, and you'll install directly from up-to-date repositories.
The catch is that you'll likely need a hard-wired internet connection, because the minimal CD doesn't load a set of Wi-Fi drivers. But if you can spare the cable, it's a quicker, less click-y process.
After running through the (text-only) installation process, run these two commands, as suggested by reader Cinnamonster:
sudo apt-get update
sudo apt-get install ubuntu-desktop
After that, you might have to restart, or enter the command
gdm to get into your desktop. But now you've got a fully functional Ubuntu system, with everything up to date from the get-go. And now that you're running Ubuntu, might we suggest our complete Getting Started with Linux series? Thanks Cinnamonster!
Minimal CD Image [Ubuntu Documentation]