At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga.
Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus.
Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
Many different ideas, practices, and forms of art have stemmed from Ancient Greece and attempting to pinpoint just which one is the most important is near impossible and frankly kind of dumb in my personal opinion. The influence Greece had on our's and many other societies can not be summed up in, "Oh, well, they sure did make those large pillars that we also have." Or, "They did some plays and now we do some plays." Everything Greece did played a very significant part in the forming of our society today and its not easy to say that any of those hold a special place above the others. But for the sake of the question, most likely the democracy since most governments are making their way towards systems that resemble it.