I've read articles about protecting wp-config.php using .htaccess as well as setting the correct file permissions but I want it all in one place. What should my .htaccess file look like and what folders is it safe to have 777 vs 755 permissions?
Generally, it's never a good idea to have 777 set on anything. Read the links Thomas provided for more detail, but as a general rule 755 for folders and 644 for files is a good practice.
I am not an expert on this, but I hear that there is no need for .htaccess if you are using newer versions of Apache (IIS had this feature for quite some time.) You can disable directory browsing in your Apache config. It is the Indexes option in the Options directive of the Directory directive.
I don't know if 777 is required by any. 755 is probably safe for content folders.