The size depends on what size drink your pouring. I like a tapered pitcher with a spout. Hope this helps.
I have to say, ever since Terry at espressoparts.com turned me onto the spouted bell pitcher, my life has never been the same. I use the 16 oz. to pour art, and the milk it makes is amazing. We all know that the bells let the milk roll around the bottom, making the really good microfoam, but the ability to pour with the spout makes it perfect. I highly recommend the spouted bell. It's made by Rattleware, and can be picked up at espressoparts.com.