Well, the president of the US has very little power over taxes. It's vague in most things, but the Constitution is pretty clear that Congress has power over taxes. Bush could say "No new taxes" because he could veto them, and sure a president has more influence over Congress, but enacting that sort of reform would be hard.

Other than that though, I like it. The rates may be a little low, and it will be hard to tax "everything" or even to define that functionally (are you going to tax the two cents I made on intrest in my savings account? Or maybe even my whole savings account? Would stocks be taxed totally, or just profit from them? How would profit from stocks or other investments be defined? What if I lose money on my investments? Do I get paid back?).

What about property or sales tax? Do those play in, or would you just have an income tax? Could people devote their 10% to Social Security and then get more back out from the system? And how would a budget work if every citizen were affecting it and had some control over it?