Set the default value for views 3 in drupal 7

so I have this exposed from and I want to change the default value when the view is displayed. I did search and found many articles on it but either they are for older versions of views or seem to be incomplete or maybe I am wrong somewhere.

Ref articles:
drupal.org/node/635242

http://drupal.stackexchange.com/questions/1812/change-the-default-select...

Most of them suggest using hook_form_alter but I think as we are using views hook form alter is called too late. How about hook_views_pre_build will that help ?

Any help will be much appreciated.

function modulename_form_alter(&$form, $form_state, $form_id) {

if($form['#id'] == 'name-of-the-views-form-displayed') {
 if (empty($_GET['label-of-the-filter']))  {
$form_state['input']['label-of-the-filter'] = 'default-value-for-filter';
 }
}
}