While reading Harry Potter and the Deathly Hallows, I was struck by how familiar the symbology for the Hallows felt. The Hallows are three ancient relics attained or created by the Peverell brothers that give the holder some measure of control over death. The relics are the Elder Wand, a wand that cannot be defeated when wielded by its master; the Resurrection Stone, a stone that can summon a sort of reflection of a person, back from the dead; and the Cloak of Invisibility, which hides the wearer from sight.
This all sounded so familiar, and it felt like Grail mythology. After a bit of research, I think I have come up with the Grail analogues. The Elder Wand or "Wand of Destiny" is obviously related to the Lance of Longinus, the "Spear of Destiny", which grants power to its holder. Like the Dark Lord, and Grindelwald before him, the Lance of Longinus was sought, according to popular myth, by Hitler, and that his suicide was prompted by its loss.
The Stone's analogy isn't as easy to come by, but I believe that it represents an equivalent to the Holy Chalice. Like the Stone, the Chalice is represented by a circle, and has the property of restoring life.
And finally, the Cloak seems to be analogous to the Shroud of Turin, the relic believed to be the burial dressing of Jesus. Like the Cloak, the Shroud is supposedly endowed with the power of protection.
Also of interest, while the Deathly Hallows were associated with the Peverell brothers, the Chalice and the Lance were sought by Percival, one of Arthur's knights (and with some irony, the source of one of Dumbledore's middle names). Fascinating parallels. I imagine that more parallels exist, given Rowling's wonderful literacy, whether intentional or incidental, and that we will have much fun identifying them over the coming weeks and years. Drawing on these sorts of parallels gives the Potter story that much more grounding in "reality", and pulls us to it more than ever.