Ran across this article on tax breaks on WaPo's wonkblog. It's a nice breakdown of how taxes favor different cohorts, based on income.
As you can see from the chart, the biggest breaks favor the very rich.
One thing I found surprising is that the mortgage interest deduction doesn't more heavily favor the very rich. The only two possibilities I can think of for that being the case are that 1) the very, very rich get almost nothing from it (as a percentage of income, at least) and 2) the biggest gainers are classified in this chart as upper middle class (doesn't seem likely, but not impossible, either).
Also, two things you can't see from this are how breaks in the inheritance tax (or aristocracy tax, as I prefer to call it) go entirely to the top 1% (might even be the top 1/2%) and the carried interest loophole that allows hedge fund managers to get their entire salary at capital gains tax rates (also goes entirely to a portion of the top 1%).
Oh, another thing that doesn't come up, that just occurred to me. You can't see the totals of the dollars for tax breaks vs income taxes. IIRC, they're almost identical numbers. How sad is that?