Unfortunately, there is no "best" form of government. Many seem to be a good idea in theory, but often fail due to one fatal flaw; the human factor. Humans cannot be trusted to govern anything. The government is often greedy and treats itself as the nation itself. Often times the members of the government forget that they are there to serve the people of the nation, not themselves or the nation itself.
People, on the other hand, are terrible. They elect the wrong politicians based on childish logic. Often it's the most popular person who get's the people's support. Unfortunately, popular usually means manipulative. People are also terrible at judgment. The common person often gets snared into the traps of devious politicians due to their lack of knowledge.
Basically, giving power to the government is like letting someone hold your uncopyrighted cure for cancer(which nobody else knows you created) along with your unsigned nobel prize acceptance speech and giving power to the people is like putting loaded guns in a piñata.
Honestly, the only government that could always work is one run by a god whose sole purpose is to spread peace, prosperity, and happiness throughout the world. Until then, we'll be in a constant struggle; but alas, such is human nature.
If you didn't learn anything from this, you were either in complete agreement with me from the beginning or you didn't pay attention long enough.