The Tax Foundation has published Comparing Popular Tax Deductions to the Bush Tax Cuts, by Gerald Prante.  Here is the Conclusion:

It is a myth that middle-class Americans are the primary beneficiaries of our income tax code’s biggest tax preferences. Instead, the truth is that most of the tax savings from the exemption of municipal bond interest and the three deductions for state-local taxes, charitable gifts and interest paid flow to people at the top end of the earnings spectrum.

Though all four of these tax preferences are popular among lawmakers, and the charitable deduction is unassailably popular among individual taxpayers, none of them is fundamental to sound tax policy, and they all cause tax rates to be higher.

Politicians can call taxpayers in the top ten percent "rich" and denounce the Bush tax cuts for flowing mostly to this group, but if they do, they must also acknowledge that the other popular tax preferences discussed here also flow to "the rich." On the other hand, if they call the people in the top ten percent "middle-class," then they can defend both the Bush tax cuts and these four other tax preferences as "benefiting the middle class." But they can’t have it both ways.