A friend asked me how important I thought the discovery of Herod's tomb was on a scale of 1 to 10: 1 being Jesus's tomb, in other words, a hoax; 10 being the Dead Sea Scrolls, meaning the find of the century. (Great scale, by the way.) My answer: A three, maybe a four. Why so low? First, Herod lived only 2,000 years ago, hardly the 3,000 of David or the 4,000 of Abraham. As a result, we know quite a lot about him. You can credibly write a biography of Herod (many have done so) based on the archaeological and historical record of his time under the Roman empire. This would be nearly impossible with David. And absolutely impossible with Abraham.
Second, Herod himself is not one of the biblical patriarchs, kings, or prophets. He's not a central player in the main storyline of the Bible, except for his role expanding the Second Temple and his role in setting in play a number of events surrounding Jesus. As a Roman client king, he was a political functionary, albeit a powerful and prolific one; not a person particularly touched with an intimate relationship with God.
This leads to the third reason: This discovery, if true, doesn't really alter what we know about the period, the Bible, or even Herod that much. It was found, for instance, in a place that already carries his name. As a result, it doesn't really touch on the great debates surrounding the Bible, religion, the veracity of the stories, etc. These, of course, are the really big questions that discoveries such as the Dead Sea Scrolls, the Gnostic Gospels, and David's kingly title have done in recent decades. Especially considering that the tomb appears to be empty (meaning it contains none of the extraordinary discoveries found in, say, King Tut's tomb), it hardly advances the story. King Herod's tomb is fascinating, titillating, and important in the story of late Second Temple Judaism, but it's not a galvanizing moment in biblical archeology or world religion.
PS: The discovery has absolutely no significance at all in the conversation between Israelis and Palestinians over who should control the the West Bank, unlike this silly assertion in the paragraph 3 of the Washington Post article on the find:
The discovery dusted off the competing Israeli and Palestinian claims to the region between Bethlehem and the Judean desert. Israeli settler leaders said the reported find of the Jewish king's tomb supported their historic right to the area, while Palestinians expressed fears that it would be used as a pretext to increase Jewish settlement construction south of Jerusalem.