Dr. Faustus

It is recognisable for its influence, and the “don't aspire beyond the human limits of knowledge” is a tale as old as time itself, but this still holds up magnificently, which I wasn't expecting.
A play written in blank verse with the theme of a repentant God, an unrepentant Devil, and a human having sold his soul to the latter in exchange for knowledge and relief from boredom sounds (and is) exciting. It helps that Marlowe keeps it simple, doesn't get too preachy, and fills up the gaps nicely even with a foregone conclusion.
TL;DR - don't sell your soul to the Devil, with a capital D - who would have guessed?

(2nd read: August 2012)

To keep in mind:

“Hell hath no limits, nor is circumscrib'd
In one self place; for where we are is hell,
And where hell is, there must we ever be.”

8/10