If you're discussing or even mulling matters of tax fairness — before or after the current Bush proposals — you need to look at this chart. It ran in this morning's New York Times and it shows that, basically, the tax burden as it currently stands on Americans is flat. Taking into account things like property taxes, payroll taxes and sales taxes, poor Americans are paying about the same percentage of their income to the government as are wealthy Americans.
Assuming this chart is correct: If you think Bill Gates should pay the same percentage of his income to Uncle Sam that you do, then fine. That's pretty much what we already have. If you believe in "progressive" taxation — meaning that the rich should pay a little higher percentage — then the current plan from the White House is moving towards the opposite goal.