I like cake.
Because Hitmonchan is not available in BW2 and is the only Pokemon to pass on Vacuum Wave to a Riolu, I have to either run a mix set or replace it with another special move for extra coverage. Probably with this moveset:
Aura Sphere, Extremespeed, Ice Punch, and Psychic/Shadow Ball/Dark Pulse
Why not Flash Cannon for STAB?