letting the "Bush tax cuts" simply expire will cause a lot of trouble, especially for those in lower-income classes

From Nick Kasprak of the Tax Foundation (hat tip: David Eplion)...

On December 31, 2010, a decade's worth of tax code changes will expire. Most pundits have been predicting for months that Congress and the President would only permit the expiration of tax cuts for high-income people, but if election year politics create gridlock, the Internal Revenue Service will be ready to roll the clock back ten years.

Most of the changes will kick in because of the sunset provisions of the 2001 and 2003 laws, known popularly as the Bush tax cuts. But other, more recently enacted tax cuts—temporary tax provisions passed in early 2009 as part of the stimulus bill—are scheduled to expire at the same time. Both sets of changes would have substantial effects on low-income taxpayers.

While many people view the Bush tax cuts as targeted towards the wealthy, taxpayers across the entire income spectrum received a significant tax cut. It's certainly true that wealthier taxpayers received a bigger cut as measured in dollars because they were paying higher taxes to begin with. However, a better measure of tax cuts is the percentage change in after-tax income, which reflects tangible lifestyle benefits...

Comparing changes in after-tax income shows that the benefits of the tax cuts were distributed much more equally along the income spectrum because the Bush tax cuts included a number of provisions targeted specifically at low-income people. Moreover, low-income taxpayers also benefited from some temporary stimulus measures enacted in 2009 that are also set to expire at the end of this year: an expansion of the earned income tax credit (EITC) and the child tax credit, as well as expanded credits for college education....

The biggest single tax cut among all the provisions in the Bush tax cuts was the introduction of a new low tax rate on the first $6,000 in income ($8,500 in 2011 dollars). Previously, taxable income up to $27,950 ($34,500 in 2011 dollars) fell into the 15-percent bracket. The Bush cuts split this bracket into two, and set a rate of 10 percent on the lowest bracket. This provision affected all taxpayers; even billionaires saw a small savings because their first $6,000 in income was taxed at the lower rate. However, the change had the biggest effect on low-income earners from a percentage standpoint....

To plug in your own example to see how a hypothetical family of your choosing, would fair under these alternative policy scenarios (as opposed to our three chosen examples above), visit the Tax Foundaton's MyTaxBurden.org calculator.