THE ANCIENT PERSIA EXHIBITION in the British Museum is covered in an article in the Lebanon Daily Star ("Ancient Persia comes alive in British exhibition"). Excerpt:

While the Athenians often defined their own democratic system in opposition to Persian monarchy and autocracy, recent scholarship has acknowledged the highly tolerant and adaptable nature of the Ancient Persians. The Achaemenid king had the title of "king of kings" as well as "king of lands," revealing the flexible nature of his rule: while the different corners of the empire were mostly ruled by satraps (governors) from the central Persian royal family or nobility in order to preserve loyalty, local kings frequently retained their thrones and countries were permitted to function as they wished, as long as the Achaemenid king received his financial dues. In return for the reaping of wealth from around the empire, the Achaemenids promised security and protection, and to back such promises they had formidable military power.

[...]

Interest in the Achaemenid Empire was renewed in 19th century Iran, and was used during the reign of the Shah Mohammad Reza Pahlavi in 1971 to reawaken nationalism when the 2,500th anniversary of the foundation of the Persian Empire by King Cyrus the Great was celebrated. Thanks to his appearance in the Old Testament, Cyrus I has been hailed in the Western world as an upholder of religious tolerance and human rights. When he conquered Babylon in 539 B.C., he reinstated religious tolerance and allowed various exiled peoples, including the Jews, to return to their homes.

The Cyrus Cylinder, discovered in 1879, on which is carved Cyrus's statement on entering Babylon, has become, perhaps simplistically, an icon of human rights. There is even a replica at the United Nations in New York. The Cylinder forms the final stage of the exhibition, suggesting that it symbolizes Ancient Persia's principal legacy. However, it is evident from the earlier displays that we can learn more today from the tolerance, flexibility and adaptability that were central to the Achaemenid Empire's administration than from an official royal statement.

I think this gets a little carried away. Although it's true that the Persian Empire looks pretty good in comparision to, say, the Assyrian and Babylonian Empires, it still was an empire, with "hegemony" and "oppression" and all those other bad things we associate with imperialism today. It was not a liberal democracy and Cyrus' liberal policies came more from expediency and enlightened self-interest than from any interest in human rights. Still, his rule does look better on that count than the government of the Mullahs in Iran today.