This one is for the people interested in who pays INCOME taxes and how much and what their contribution is to the national tax receipts.
The IRS breaks down income tax stats by income group. If you follow this link, you'll have to negotiate a rather busy page of links to various tables.
But it's worth it to see how the economy is doing (less wages=less taxes) or if you want to wade into the waters of tax politics. Just remember, this represents INCOME taxes - not payroll taxes, sales taxes, property taxes or which socio-economic groups serve in the military ;)