My favorites are every one of peins attackes, because being able to control six bodies at once by piercings is amazing.=] And being able to remove souls is very amazing.=] But the attacks when Sasuke's Curse Seal is activated are pretty Amazing..
"The corpse's bitter crimson tears flow and mingle with the endless sand, filling the chaos within me - and making me stronger."
Personally my favorite special is Orochimarus Reanimation Jutsu and his Three Rushoun Wall Summon
But i mainly like his reanimation move because he can summon people back from the dead and if he wanted to he could even bring the 4th hokage back to life i mean he could summon the 1st,2nd,4th hokage whats more better then that with all of them on his team he would be practicaly unstoppable.
But on ultimate ninja 4 i do like how orochimaru can summon manda thats probably my favorite special from any of the games.