I dunno whether this was mentioned before or not, but I'm having troubles with the_content() function in single.php.
Let's say I have a post cut in two pieces (they stand for: piece 1 is a teaser and the second one is a main content, displayed in single.php) by the "<!--more-->" tag.
Now, the issue is that I see nothing in single.php instead of the content. This is not a theme problem, because this appears no matter what layout is currently in use. Teasers (before the <!--more-->) are displayed correctly in archive page, front page, etc. It's only about single.php.
May be helpful: $post->post_content returns all content properly.
Forgive me if I'm duplicating another thread now.