Testing on MWS- here's what I've got.
// Deck file for Magic Workstation (http://www.magicworkstation.com)
// Lands
1 [AQ] Strip Mine (2)
4 [AN] Bazaar of Baghdad
4 [[card=02082]TE[/card]] Wasteland
// Creatures
4 [U] Nether Shadow
4 [RAV] Stinkweed Imp
4 [TO] Ichorid
3 [RAV] Golgari Thug
4 [RAV] Golgari Grave-Troll
2 [RAV] Flame-Kin Zealot
4 [FUT] Narcomoeba
2 [ZEN] Iona, Shield of Emeria
// Spells
4 [FNM] Cabal Therapy
3 [TSP] Dread Return
4 [GP] Leyline of the Void
4 [DS] Serum Powder
4 [FUT] Bridge from Below
4 [MR] Chalice of the Void
// Sideboard
SB: 2 [SC] Dragon Breath
SB: 3 [TSP] Ancient Grudge
SB: 4 [MM] Unmask
SB: 4 [FUT] Dryad Arbor
SB: 2 [WWK] Novablast Wurm
So...I'm trying to SB to respond to the Pithing Needle- Dryad Arbors and Ancient Grudge seems the best way to do that. Unmask goes in pretty much second match anytime to try to stay ahead of Yixlid and Pithing Needle. Then finally, Platinum Angel has been being a pain in the rear, so after I mop up with the Zombies, I flashback Dread Return on the Novablast Wurm/Dragon Breath to Wrath the board.
Iona can hose Yixlid if you get to it fast enough, or mono-blue tricks, or even the mirror matchup (black hoses Dread Return).