Before Katrina, there were also the July 7th terror attacks in London. This would have been the first major international event Cheney has to handle as President. Assuming no meaningful butterflies, of course.
With both the leaders of the US and Georgia dead in early 2005, I think we can safely say the 2008 war in Georgia would be butterflied, at least as we know it. Who, for example, could we expect to replace Saakashvili and what would be his/her policies towards the US and Russia?