WordPress currently replaces "regular" quotes with “fancy” quotes by default, and there is no way to turn this off other than hacking away at wp-includes/formatting.php
Fancy quotes are fine in English, but other languages have other needs and WordPress should accommodate that - at least in so far as letting users turn off the automatic conversion and using whatever quote style they want.
For e.g., Hebrew uses regular quotes and not fancy quotes, but currently Hebrew users using WordPress get fancy quotes in all their posts.
I propose adding an option for turning off fancy quotes, in the same way that emoticons can be turned off in Writing page of the Settings section in the administration interface.
Alternatively, WordPress can automatically default to the correct quote style to use according to the locale set in wp-config.php, or according to a variable set for every local distribution.