Although this is the only shampoo that I have used on my yorkie, I defenitely reccomend it!
I asked this question awhile ago and one of the shampoos reccomended to me was Espree. It was the only one on the list that was available at a chain pet store, rather than a groomer or online.
This is the kind we got for Buddy, it smells really good, he has soft fur and it comes in a very nice sized bottle and will last a long time with a yorkie sized dog!
Espree Natural Oatmeal Baking Soda Dog Shampoo at PETCO