You can personalize web site for various kinds of content... for instance, on home page: 1 column, on category listing: 2 posts, on single article: 3 posts. In Wordpress the correct answer is easy, modifying home.php, category.php, single.php.

Using what conditionals I'm able to make this happen in Joomla 1.5?

Thanks

You are able to conditionally display modules on the page by page basis (according to food selection). You may also assign different templates to every page. In addition, that you can do such things as

$option = JRequest::getCmd('option');
$view = JRequest::getCmd('view');

in your index.php and alter the page in line with the view/component.

Joomla's templating is great, with many different versatility.

If perhaps one column consists of the actual content (componenent/article) you might use retractable module positions. Such as this:

<?php if($this->countModules('left')) : ?>
    <div class="left_column">
        <jdoc:include type="modules" name="left" style="xhtml" />
    </div>
<?php endif; ?></code></pre>

Then your presence or lack of modules within this column determines design.