Steven Landsburg, guest-blogging at The Volokh Conspiracy, points out the real beneficiaries of disaster recovery:

There has long been an expectation that in Katrina-like circumstances, the government will step in to help. That makes disaster-prone cities like New Orleans (and, among others, San Francisco) more desirable and pushes up land prices in those cities.

So if you own a house on a flood plain, chances are the purchase price included a premium for the disaster insurance that the government insists on providing. That's a boon not to you, but to the former owner, who might live in Montana by now. The wealth transfer goes not to those who are currently in danger, but to those who owned endangered property when the policy went into effect.

I would add one additional effect: the expectation of government help is based largely on precedents; and congressmen voting on emergency relief measures will feel the effects of this. Even if they do not see the connection Mr. Landsburg points out, their land-owning constituents surely do. Thus a vote for New Orleans reconstruction funds made by a representative from, say, California has the effect of rewarding the wealthy Californians at the expense of the poor.