There are many modules that provide some sort of slideshow / rotator functionality.
This page summarizes the usage of all projects on drupal.org. For each week beginning on the given date the figures show the number of sites that reported they are using (any version of) the project. Detailed usage information for each release of a project is available by clicking the project name.
Modules for uploading and managing files, and associating them with content.
overview drupal client-/server-side form validation modules
gibt auch einen guten überblick zu modulen, die gleiche funktionalität haben, die man aber noch nicht kennt
Die CMS Drupal, eZ Publish, Plone, Joomla und Typo3 im subjektiven Featurevergleich