Build menu like this in drupal 7 I have always been working on drop down menus which nice menus or sucker fish menus was satisfying. I have a new kind of menus to be satisfied.  As show in the image. When destination is hovered its should bring out drop down in that manner.
I would use the Superfish module (http://drupal.org/project/superfish), recently this has added an option for megamenu which will allow you to build a display much like your screenshot. You will need to tweak the css to get the display how you would like it.

Demo: http://mehrpadin.net/demo/superfish/ (hover over "products" in the very bottom menu)