R – best approach to render site-wide elements using Zend Framework

You can use the ActionStack helper. For example:

class MyController_Action extends Zend_Controller_Action {
    function init() {
        /** you might not want to add to the stack if it's a XmlHttpRequest */
        if(!$this->getRequest()->isXmlHttpRequest()) {
            $this->_helper->actionStack('left', 'somecontroller', 'somemodule');
            $this->_helper->actionStack('center', 'somecontroller', 'somemodule');
            $this->_helper->actionStack('right', 'somecontroller', 'somemodule');
        }
}

class MyController extends MyController_Action {
    function indexAction() {
        // do something
    }
}

class SomecontrollerController extends MyController_Action {
    function leftAction() {
        // do something

        $this->_helper->viewRenderer->setResponseSegment('left_container');
    }

    function centerAction() {
        // do something

        $this->_helper->viewRenderer->setResponseSegment('center_container');
    }

    function rightAction() {
        // do something

        $this->_helper->viewRenderer->setResponseSegment('right_container');
    }
}

A request for /somemodule/my/index results in executing /somemodule/somecontroller/left. /somemodule/somecontroller/right, /somemodule/somecontroller/center which end up in the correspondig layout segments.

First advice is to avoid the Action view helper at all costs, it will probably be removed in ZF 2.0 anyway. (ZF-5840) (Why the actionstack is evil)

This is related to a question I asked - and bittarman's answer is pretty useful. The best way to implement something like that is to have a view helper that can generate your "login" area. My_View_Helper_Login for instance. Then your layout can call $this->login(), and so can the view script for user/login. As far as having index/index render the content from news/list just forward the request to the other controller/action from the controller. $this->_forward('list', 'news');