WordPress File Permissions

Hi everyone,
I would like to clarify one thing that concerns me.
It is suggested in the WordPress docs that all files should have 644 permissions and all directories 755
However, I read here http://codex.wordpress.org/Hardening_WordPress :

find [your path here] -type f -exec chmod 644 {} \;
You have to omit to use this command for /wp-includes/.

Are there any files in /wp-includes/ that require other permissions?

I read also at WP Forums about some exceptions but without any clear examples…
So, lets clarify this – all files in WordPress directory and sub-directories should be 644 or there are some exceptions? And if they are then which files should have other permissions?
Thank you in advance for any help.
Chris