Problem/motivation
As found with multiple participants in http://groups.drupal.org/node/274458 and before in discussions, some people assume they set up a multilingual site while others assume they set up a single language foreign language site. When a user chooses a language in the Drupal installer, that language is used for installation, the localizations are downloaded for that and the language and interface translation modules are enabled. This ensures Drupal can work in the foreign language and is the ideal setup for a foreign single language website.
Drupal cannot assume that the user wanted a multilingual site. It might be a good idea however, to give an option in the installer, if the user is already setting up a foreign language site to enable multilingual content (and preconfigure some content type language settings based on 80% defaults out of the box). This would be similar to the checkbox to choose to install the update status module.
Proposed resolution
Figure out if we want to have this feature and if we do, implement.