I'm in my module file. I want to define some complex variables for use throughout the module. For simple things, I'm doing this:

function mymodule_init() {
    define('SOME_CONSTANT', 'foo bar'); 
}

But that won't work for more complex structures. Here are some ideas that I've thought of:

global:

function mymodule_init() {
    $GLOBALS['mymodule_var'] = array('foo' => 'bar');
}

variable_set:

function mymodule_init() {
    variable_set('mymodule_var', array('foo' => 'bar'));
}

property of a module class:

class MyModule {
    static $var = array('foo' => 'bar');
}

Variable_set/_get seems like the most "drupal" way, but I'm drawn toward the class setup. Are there any drawbacks to that? Any other approaches out there?