I would say "Communist", but due to the complicated nature of using that term I will spell out a few basic rules I believe a good government would follow:
1. It is run by all of the people, for all of the people. Minorities enjoy the same status as the majorities; no ethnicity, religion, sexual minority, gender, nationality, politics, philosophy, race, color, or other preference,viewpoint, or biological trait should be placed in a subservient position.
2. It is run by all of the people, for all of the people in a democratic manner. Through accountable representatives, councils, direct democracy, or systems that employ a number of these methods.
3. There is a distinct and independent judiciary; it has the power to check the will of other political branches as well as the people. It is used to protect the minorities and the majorities, uphold the law and stability of the nation.
4. The government, at all times, attempts to enforce the following concepts and meet the following goals:
Survival
Stability
Common Prosperity
Equality
Justice
Liberty
In order of importance, actually.
5. It would be best if it accomplished these things without a cumbersome bureaucracy or an overzealous police force. Some things should be allowed for given emergencies and circumstances beyond the control of that government (natural catastrophe, war, plague).
6. War is a defensive measure, it should not be used offensively unless under extreme circumstances or in the defense of a progressive nation or entity. (Let's say, to defend a Social Democracy against a Fascist Dictatorship.). At all times a government and the people that support it should not only protect their rights and freedoms but those of people around the world.
7. The economy must be kept in the hands of the working people. No corporation, government, or over-powering entity should control the economy. As such, the government should provide a supplementary role in the economy through grants, loans, and control only those parts of industry and commerce absolutely necessary for the people's and the economy's stability and prosperity. (Heavy industry, resource collection, mass transit, some media, Space..etc..etc..)
Additionally, non-democratic economic entities such as corporations, partnerships, sole proprietorships..etc.. should be kept relatively small (or non-existent). Small family businesses, coops, family farms, non-profits, and some forms of sole proprietorships should be the major driving forces of the economy.
Remember, whosoever has the money has the political power. If everyone had about the same economic power they'd also have about the same political (or potential, as not everyone uses this power).
I think that covers the most important stuff. Not exactly a concise and full description, but a start I suppose.