I'd say 2006 and 2007 were worse than 2008 and 2009, if only because Iraq was going sideways in a hurry during that time. The economy was better in '06 and '07, of course, and Afghanistan was marginally less of a mess (or, at least, we weren't aware that it was such a mess), but I really don't think that outweighs the US casualties in Iraq during that time, not to mention the massive amount of Iraqis who died during our watch.

Of course, I'm just looking at this from a perspective of an American. I have no idea what year was worst in the grand scheme of human events.

In fiscal years...June 08-09 was the worst of the bunch. I have never seen such massive destruction of wealth, so many acquaintances lose their savings and livelihoods...