Magento Design Patterns

Question

Magento, IMHO, represents a PHP system that is built on well thought-out coding principles - reuseable design patterns being one of them. In terms of an example of a PHP system

Answer 1

A few more:

Event/Listeners:

Mage::dispatchEvent('model_load_before', $params); 

And of course, MVC, with Views being represented by a combination of XML, PHP Classes, and PHTML templates.