A major reorganization of power comes about. The United States' position as the world's driving political and economic force is diminishing as China, India, and Brazil gain prominence. In China this growth comes with some degree of political upheaval. The growth of a wealthy middle class leads to the liberalization, and eventual democratization of the nation. Power also gets redistributed on an individual level - with better access to education and information, people now have a lot more social mobility and effective influence in their governments. Investments in science, technology, and space exploration come not from governments, but wealthy individuals and businesses. The first colony on Mars is a multinational effort backed by Google, Microsoft, Virgin, Ford, Coca-Cola, and other big-wigs.

Computing power becomes exponentially cheaper and ubiquitous. Robots take over almost all labour and manufacturing jobs, causing unemployment and depression for a while. However, social changes are also taking place - birth rates stop increasing, and begin to turn downwards by 2075. Genetic modification is available to everyone, improving quality of life around the globe.

Everything isn't perfect, however. Tensions in the Middle-East rise between Israel and Iran. The US, at this point decides to back away because of domestic pressures. Nuclear missiles are exchanged for the first time in over half a century - Tehran and Tel-Aviv are destroyed. Shocked, the international community intervenes immediately (not nuclear), with the US occupying Israel, and Russia Iran. However, instead of a East/West Germany-esque scenario, the world powers decide to work together to diffuse the situation.

By the end of the century, humanity is fewer in number, smarter, and healthier. We occupy the land and oceans of Earth, as well as colonies on the Moon, Mars, and on the moons of Jupiter.

Edit: I just remembered reading this last week, you may enjoy it - http://www.dni.gov/index.php/about/organization/national-int...