Toolkit
Toolkit modules:
Drush - administer Drupal at the command line
Devel - mainly useful to see page load time (from PHP's perspective), view the database queries, and aid with development (i.e. which function generates which HTML and what function name we can use to override it)
Masquerade - to test user permissions rather than create test users
Translation Management - to see which strings need to be translated or not
Strongarm - hardcode settings in a developmental module
Update Status Advanced Settings
CVS Deploy
Administration menu
Backup and Migrate - automated database backups on- or off-site
Install Profile API
disable after running install profile
uninstall altogether, including delete the files?
Modules unnecessary for rendering the site:
Views UI - only needed by admins, can be disabled to get a tiny performance increase
Memcache - for monitoring stats only, doesn't provide functionality