[eluser]brandon.cordell[/eluser]
constant variable is kind of an oxy moron hehe :-P
application/constants.php holds pre-defined constants. Why not put your constants in there?
You can also create another php file in the aforementioned application/config directory. Then in your application/config/autoload.php you add your config file name to the $autoload['config'] array.
Code:
$autoload['config'] = array('config, another_config');
Use the name of your config file without the .php file extension.