The constitution should reflect only the ideals and purposes of this state. Any actual implementation will be contained in a set of bylaws or procedures referenced in the constitution.
The most basic pretense of this constitution is to protect the freedom and privacy of the citizens.
I am very much of the opinion that this may develop into a libertarian state. Such freedoms as the right to bear arms (the only one I have ever opposed, and the one I have recently come to accept and embrace) are explicitly stated. Also stated is the idea that no object is in itself wrong -- a gun, a computer virus, etc -- only actions can be criminal.
The only criminal acts should be those that negatively impact the freedom, privacy, or prosperity of a citizen. International crimes will correspond to the existing treaties, in order to avoid any conflict with other cultures.
Some activities that may be criminal in other societies, may actually be rewarded. For example, it is not illegal to create a computer virus, however it would be illegal to propagate it and infringe on the prosperity of other citizens. However, if the source code to the virus is presented to the correct government agency (and therefore made public), a reward will be presented for making us aware of a weakness in some existing system (but an explanation of the weakness and an actual solution would probably garner a larger reward).
Prostitution and narcotic drug usage will not be illegal, but government subsidized, in order to prevent the health risks and other negative aspects involved in the blackmarket peddling of these products/services.
Openness in the government is paramount. Every aspect of it should be visible to the people, and various levels of (non-government) filtering should be available in order to make the issues and policies accessible to every citizen.
In fact, an agency will exist whose purpose is to monitor the activities of leaders and diplomats, in order to ensure that all governmental matters are disseminated while protecting the privacy of said leaders from the general public.