Great start guys!
I have a few suggestions:
1) The Tax Rate
Earlier there was a suggestion to limit the taxation rate in the constitution at a specific percentage. I agree with this, but I would take this a step further and say that the taxation rate should also not exceed a specific dollar amount. In order to fluctuate with the increase in population and with the growth of wealth, this amount should not be explicitly stated in the constitution as a number, but instead it should be devised as a formula to be calculated and pronounced yearly or every decade.
My idea for this amount would be to take a government estimate or tally of the average yearly income of a citizen, and to limit the amount at a percentage of that amount. We'll call this the explicit income ceiling, because it is an amount of income determined explicitly (yearly, or every decade, or whatever) that caps the amount that you can be taxed.
For example, say that the maximum taxation rate in the constitution was 20% (for the sake of this example). Then say that the current income tax rate was set at 10%. This is a valid rate because it isn't greater than 20%. Now say that the constitution also limits the rate determining the "explicit ceiling" amount to this same 20% value, however, it allows the rate to be lower than that 20%. So let's say that it has been set at 15%.
So, in this hypothetical:
The income tax maximum is 20%
The explicit income ceiling maximum is also 20%
These two values are in the constitution and are permanent.
The income tax rate for ALL people is currently 10%
The explicit income ceiling for ALL people is currently 15%
Let's say:
That the average yearly income is $30,000.
Peter made $15,000 this year. 10% of $15,000 is $1,500. 15% of $30,000 is $4,500. Peter pays $1,500.
Paul made $1,000,000 this year. 10% of $1,000,000 is $100,000. 15% of $30,000 is still $4,500. Paul pays $4,500.
Mary made exactly $30,000 this year. 10% of $30,000 is $3,000. 15% of $30,000 is again $4,500. Mary pays $3,000.
Let's say that after a year of inflation, everyone's wallet has been flooded with dollars that are now worth half as much as before.
The average yearly income increased to $60,000 (due to inflation this is worth as much as before)
Peter made $30,000. He pays $3,000 (the same value as the year before)
Paul made $2,000,000. He pays $9,000 (the same value as the year before)
Mary made $60,000. She pays $6,000 (again, the same value as the year before)
In this way the explicit taxable income ceiling always adjusts for inflation or deflation, whereas specifying a dollar amount in the constitution would not.
This system would definitely favor the rich and because of the elimination of tax brackets there is no discrimination against them. As the average yearly income in America increases, so does the amount of the explicit taxable income. This would encourage people to become rich, however it might also encourage the rich to keep the poor and middle class from raising the average yearly income. This is an interesting problem, but it may perhaps be solved by instead setting the explicit taxable income to a value in the constitution and to always adjust it year to year based on a government calculation of inflation.
2) The Voting System
I've always thought that the voting system in the United States is entirely too simple. I also think it promotes the two party system, blocking out all 3rd party candidates.
For presidential and legislative votes held by the public, I would suggest something like ranked ballots. You can do a ranked ballot several ways, but the main point is that if your primary choice is extremely unpopular and it is as if you've wasted your vote, you will still have an impact on the vote by the way you ranked your other choices. This basically means you get more than one vote. Whether or not those votes are worth the same or if your primary vote is worth more than your secondary vote or if you get 3 or more votes all depends on the type of ranked ballot.
Look ranked ballots (also called "preferential voting") up on wikipedia for a more thorough explanation. Currently, the "one vote" system that we have is definitely the simplest, but it causes a lot of untold problems (chief among them is the two party system). There are TONS of voting systems, such as preferential voting, or instant-runoff voting. One of the biggest goals should be to decrease the effects of gerrymandering and to decrease "wasted-votes". The only problem may be the introduction of "tactical voting".
3) The Money Problem
Who should print the money? Is money going to be backed by anything (such as a metal, or a commodities market, or something else). Is money printed by the government, or are separate currencies allowed (such as private bank notes)?
My personal take on this would be to have the government print the common currency. I have no rational opinion about backing it with something or having it be just be worth the paper it's printed on.
In addition, the major change I would make is to allow private currencies that can be used as cash. The government should only accept the common currency for taxes and fees, however business should not be required to accept the common currency, or required to pay their employees in the common currency. I'm sure the free market will provide for currency conversions.
Something needs to be done about the Federal Reserve problem, but that can be left to someone else to debate. The common currency should definitely be printed by a government agency and not by a private organization.
4) The Corporation Entities
Legally, corporations need to be considered as groups of individuals instead of large entities. Currently, the government treats corporations as people, with rights. Corporations don't have any rights, just the individuals they are composed of. This has allowed them to abuse the system in different ways, and in-turn be abused. I would imagine some of you would think that they should be treated like people as this affords them benefits and you might think this promotes the activities of a free-market, but I disagree. It is simply not true that they are individual entities. The individuals they are composed of must be held accountable for their individual actions. The biggest benefit that this bestows on them is the elimination of corporate taxation. In effect, all businesses would be considered groups of contract workers by the state, instead of being employees of a specific company. This would be a part of the separation of the economy and the state, since the government would also never be able to mandate a minimum wage, health benefits or anything else. But this also means that a corporation as a whole cannot be sued, only the responsible parts of it. For instance, a patient would sue an individual doctor instead of the hospital he works for. To entice skilled doctors to work for them, however, the hospital may have made a deal to absorb most, if not all, lawsuit damages.
5) The Incumbents
I agree with limiting the number of terms of ALL elected officials to a maximum of 2 or 3 non-consecutive terms.
I would venture to add that in a time of war, the incumbent president may be re-elected for his second (or third) consecutive term. This way, a war-time president can stay in office if the people think he is handling the situation adequately. This limits the damage a new president can cause during the transition period. An argument against this suggestion would be that presidents would start wars just so that they could stay in office for consecutive terms, which would be very bad.
6) On Legislation
In order to prevent legislation without representation, require that the congressmen has read the bill he is voting on and that it was written by the hand of an elected congressmen (not an aide). In addition, the bill to be voted on must be read in front of the legislative body after a vote is called, but before the vote is performed. Also, all legislation must be released for public review for at least a set amount of time (equal to or greater than the amount of time needed to read and analyze the bill) before a vote can be called, and if it is changed after it is released then it must be released again. This basically boils down to requiring congress to release a bill they are going to vote on so that the news stations can get a hold of it and publicly criticize everything that's wrong with it.
Each piece of legislation should also require the appropriate passages in the constitution that provide the powers that are used in the bill. This will help cut down on unconstitutional garbage getting through, in addition the above paragraph about releasing the bill provides that this constitutionality statement is checked against the facts in the bill.
Lastly, the bills should have a title that accurately represents their contents and they should be limited to one subject at a time. Therefore no large stimulus bill could ever be enacted that has such varying consequences as bridge building in one state and an housing project in another. This would basically stop congress from adding pork to their bills. If not enough congressmen want a bill, then this should stop them from compromising. Also, the "Patriot Act" and "The American Recovery and Reinvestment Act" would be good examples of names that do not accurately reflect the nature of the bill. The name of a bill should not be misleading.