What is the meaning of the Second Amendment to the Constitution?

I'm still not sure how I feel about guns so my answer isn't diluted with an agenda. Basically, the 2nd amendment is the right to bears arms for a well regulated militia. You see, this was written before the United States had a military. Some people think the idea was, if the public has the right to bear arms, they can defend themselves from invaders. At this point though, the public wouldn't be called upon to defend against invading forces. We have a military for that. However, some think that the founding fathers were so ahead and so intelligent that the right to bear arms is a way for the public to protect themselves from a govt. that could become tyrannical. In the event that our own govt. became oppressive and totalitarian like, we would be able to rebel. Our constitution was written by the most famous rebels of our time. If one studies other forms of government, he will find that communist totalitarian regimes do not allow their citizens to own guns because they fear a rebellion. So, I think that the idea behind the 2nd amendment was to make sure that the public can protect itself from oppressive government. I just don't think the founding fathers ever imagined that governments would possess weapons that are so far beyond the capabilities of guns, that guns wouldn't protect us from those weapons.