Hurricane Gustav is presently a Category 3 hurricane. By contrast, Hurricane Katrina "weakened before making its second landfall as a Category 3 storm on the morning of Monday, August 29  in southeast Louisiana."
However, perhaps we focus too much on storm strength, and not enough on the the strength of Louisiana's engineering. Huricane Katrina herself was not what caused so much devastation in New Orleans in 2005. Rather, it was the flooding caused by failure of the levies and pumps that killed people and destroyed property. Lousy engineering -- not high winds and rain -- was to blame for the catastrophe.
Why is it that the US news media constantly reports on the power of the hurricane, yet asks few questions about New Orleans' levies and pumps? To what extent have these been upgraded? It's been three years. The politicians are silent on this issue.
This video explains what really happened in the aftermath of Katrina, and debunks some common misconceptions: