3-column layout AND 2-column layout

Administer/Site Building/Blocks

You can make certain blocks appear (or not appear) on designated pages.

You could assign all the common blocks to the right side, and the "special blocks" to the left side (the THIRD column!)

Then for each block that is assigned to the left side, press the "configure" link, and tell that block to ONLY show on the pages you want to be THREE columns.

All the other pages will show two columns because nothing is assigned to the left side on those pages (and it disappears by itself).

Themes like garland solve the two or three column layout problem inside the template. Be sure to take notice of the way it is done because otherwise your layout might not look ok.

So for example if the right column is the one which is not on every page then make sure your theme does something like this:

<div id="mainContent" class="<?php if ($sidebar_right != "") echo 'three'; else echo 'two'; ?>ColumnLayout">

Then in your css do something like this:

.twoColumnLayout #mainContent {
    width: 500px;
}

.threeColumnLayout #mainContent {
    width: 300px;
}

#sidebarRight {
    width: 200px;
}

In this way you put in the style for both options (two and three column) but you let the template specify which style should be applied. By using the suggestions the other posts gave you you are ready for using a flexible layout. btw... I would advise to make your own theme. Looks better I think :P

I hope this was helpful information at all. This can be found in the garland them if you look into the code after all....