Constantine, the first Christian emperor. This was the first time Christianity was recognized by the state; much of A.D. history (but not necessarily most) revolves around the interplay between church and state, most namely the institutionalized Catholic church and protestants.

Similarly, it follows that Martin Luther (not King), one of the vocal leaders of the protestant reformation, was influential with his 95 theses.

Jesus Christ (and the story of the man) obviously has made one of the most global and lasting impacts on culture and humanity.

I'd agree that Pauline literature largely shapes the perception of Christ and Christianity, so Paul is an important figure.

The Beatles - Shifted culture significantly, not just in the US but around the world.

Certainly Dennis Ritchie.

Vannevar Bush, who first conceptualized hypertext via the Memex in the mid-20th century.

Tim Berners-Lee.

I lightly tread and say Mark Zuckerberg, but really I mean the brainpower behind Facebook. Regardless of staying power, to have a massive enough sum of people to start saying things like "1 in 13 people on earth", it certainly is one of the most far reaching and adopted efforts in history.

Albert Einstein - the theory of relativity shapes the way a lot of modern physics are approached.

Adolf Hitler.