Your math is right,
but...
All the tax cuts that are being proposed by George W. Bush will help the rich mor than the poor, even if you figure the tax as a percentage.
The taxes that Republicans want to cut, such as the estate tax or the capital gains tax, are taxes that poor people generally don't pay at all; middle-class people pay in small amounts, and rich people pay a great deal of. A cut in the estate tax, for example, will help only 2% of Americans, and the richest Americans of all will get the biggest benefits.