Based on your question, it sounds like you were asking how to do this on a view-by-view basis.
This is where $scripts_for_layout comes in useful.
You just need to make sure that it's in your <head> tag in /app/views/layouts/default.ctp as <?php echo $scripts_for_layout; ?>
Then, you can literally add the code you included in your question into any of your views, at literally any point you like. Because you have 'inline' => false it won't actually appear at that position in the view:
<?php $this->Html->css("css_file", null, array("inline"=>false)); ?>
...and you'll find that css_file.css is automatically linked in your <head> whenever that particular view is loaded. This is a great way to only load specific CSS files on a per-view basis when they're needed, yet make sure they appear in the <head> tag where they should be.
This also works for JavaScript as follows:
<?php $this->Html->script("js_file", null, array("inline"=>false)); ?>
If you want to have one or more CSS files loaded in all views, just put a shortened version your code in the <head> of default.ctp as follows:
<?php echo $html->css(array('each','one','of','your','css','files'));
Or, again, for JavaScript:
<?php echo $html->script(array('each','one','of','your','js','files'));
Don't include the .css or .js extension in the array.