Chaos tool suite (http://drupal.org/project/ctools)
A library of helpful tools by Merlin of Chaos, for use by other modules.
Google Analytics (http://drupal.org/project/google_analytics)
Requires a Google Analytics account.
Adds Google Analytics javascript tracking code to your site's pages.
Feeds (http://drupal.org/project/feeds)
Requires Chaos tool suite.
Aggregates RSS/Atom/RDF feeds, imports CSV files and more. If there is content outside of your site that you'd like to either import into or display on your site, take a look at Feeds.
Storm (http://drupal.org/project/storm)
"Offers a hierarchy of content types to help with project management. Organizations, Teams, People, Projects, Tasks, Tickets, Timetrackings, Notes, Knowledgebase, Invoices, and Expenses."
Webform (http://drupal.org/project/webform)
Enables the creation of forms and questionnaires.
Flag (http://drupal.org/project/flag)
Create customized flags that users can set on content.
Printer, e-mail and PDF versions (http://drupal.org/project/print)
Adds a printer-friendly version link to content and administrative pages. Creates a printer-friendly version of content with more than just formatting differences. For example, it automatically creates footnotes for links indicating the URL.
Custom Breadcrumbs (http://drupal.org/project/custom_breadcrumbs)
Allows administrators to define custom breadcrumb trails for each node type.
Submitted By (http://drupal.org/project/submitted_by)
Requires Token.
Customize the Submitted by username on date text on a per-nodetype basis.