Do you have a 960 grid system installed in your WP theme? By using this plugin, writing the post/page content is become very easy. No more typo-error and no need to remember one_fourth, two_third_first or first_for_the_last. You just need to know your grid number for your content such as 9 grids content with sidebar for 12 grid system.

Demo:

http://codecanyon.net/item/960-grid-system-shortcode/full_screen_preview/725143