Now, while looking through the Odyssey spoiler, I came across many many great cards, two of them being Traumatize and Haunting Echoes.
Card Name: Traumatize
Mana Cost: 3UU
Type & Class: Sorcery

Card Text: Target player puts the top half of his
or her library, rounded down, into his or her graveyard.
Card Name: Haunting Echoes
Mana Cost: 3BB
Type & Class: Sorcery 
Card Text: Remove all cards in target player's
graveyard other than basic land cards from the game.
Search that player's library for all cards with the
same name as cards removed this way, and remove them
from the game. Then that player shuffles his or her
Now, assuming you aren't playing against a person that plays with single copies of spells, this will severely cripple a person.  First putting half of one's library into the graveyard, then, most likely, eliminating the other half with haunting echoes.  And since it's black/blue, feel free to add in a couple of Lobotomies.  Even any of these alone will hurt.  Millstone, discards, etc will help with the Haunting Echoes, and Traumatize in my mind is a trade off version of Denying Winds.  I mean, they'll probably lose more cards for a smaller cost, but you don't get to pick the cards lost.  So...I dunno.
However, going through the spoiler list again, I came across another card:
Card Name: Nefarious Lich
Mana Cost: BBBB
Type & Class: Enchantment

Card Text: If you would be dealt damage, remove
that many cards in your graveyard from the game instead.
If you can't, you lose the game. If you would gain
life, draw that many cards instead. When Nefarious
Lich leaves play, you lose the game.
Now, if anyone remembers Lich from the old days, this is pretty much the same card, but instead of sacrificing permanents, you're going to remove cards in your graveyard.  But ignore that for a moment, and go to the last line.  Donate and Boomerang/misc other way to make stuff leave play.  BE VERY CAUTIOUS WHILE DOING THIS, however.  If you lose the other great Donate/Boomerangable card, Illusions of Grandeur, you're really not losing anything.  However, if someone Boomerangs this or even Disenchants it, you're screwed. 
Granted, these comboes are pretty costly mana-wise, but hey, that look on your opponent's face will be priceless.  And don't forget to stock up on the countermagics.