From the Washington Post, here's a bit of visual education (click to enlarge):
Under McCain's tax proposal: The bottom three groups, which amounts to 60% of taxpayers, will have their taxes cut by .2-.7%, or roughly $19-$319. People who make above $2.7 million, however, will have their taxes cut by a whopping 4.4%, or roughly $269,364.
Under Obama's tax proposal: The bottom three groups will have their taxes cut by 2.4-5.5%, or roughly $1,042-$567. For those making above $2.7 million, their taxes will increase by 11.5%.
Under McCain, the rich stay rich and the poor stay poor. Still confused? Read this CNN article that takes a closer look at the proposals.
And no matter your party, please look through FactCheck.org. It's an unbiased site that investigates the truth and lies behind advertisements, speeches, and quotes/interviews. Know the facts before you vote. Knowledge is power, guys.