fwiw, i'm kind of thinking that what i'm going to do is pick one extra berry, based on price, and modulate back and forth. those would include blueberries, raspberries, cranberries, blackberries and currants - i'll just grab whatever's on sale. 

the raspberries & blackberries are probably a little better, but they just don't last; the cranberries & blueberries have longer shelf lives, but they're both pretty nutritionally inert, really. 

it'll be opportunistic, rather than routine - that's what i'm thinking is the better approach.