Whenever one of my recipes calls for cocoa, I always turn to Hershey's. It is a high-quality cocao and all of my family members love the taste when I use it.
The best cocoa powder I use if bought at the health food store. It is organic - Raw Chocolate Powder CACAO POWER from Navitas Naturals. It make anything I bake taste so chocolaty and tasty without using large quantities and there is no sugar added. Love the stuff!
I also prefer Dutch cocoa, but you can change the chocolate cream you use by using couverture chocolate, this will give you the "extra dark" gourmet taste.