In terms of the utilization of the screen real estate, vertical menus make much sense as there is more width then height in a typical display monitor. I think the way to use the WP 2.7 menu system is in its iconic mode. It takes much less space, options are one click away upon hover, and always visible.

I am not a fan of drop down selections outside the obvious choices, like selecting years, states, and the like. Otherwise, the menu selections are always hidden with no hint of what may be possible. In this case, simplicity hides affordance and structure. Try the iconic version of the 2.7 menu and see what you think.