Base URL in Drupal 7 settings.php
Added a StartSSL certificate today to a site and after all was done the style sheets wouldn't load when accessing with https. The culprit turned out to be having
<?php $base_url = 'http://www.example.com'; ?> set in settings.php. After commenting that all worked fine.
The certificate from StartSSL is their free one until I decide whether I really need it. I'm testing the Drupal for Facebook module and the Facebook canvas part requires https after October 1st.