Depends on your spec, glyphs and how much spell power you have (85 values here) ...

Code:
Felstorm ((($SP * .50) * 2) * 0.33 +  158) 
Legion (($SP * 0.50) * 2) * 0.264 +  138) / # targets
Firebolt ((($SP * 0.50) * 0.657) +  124)
Lash (208 + (0.612 * ($SP * 0.5)))  
Whiplash (475 + (0.85 * ($SP * 0.5))) 
Bite (70 + (0.614 * ($SP * 0.5))) + 15% each dot
... I would think that Spell Lock/ Devour Magic, Seduce/ Whiplash and Axe Throw would all have merits beyond what the actual pet does for damage.