I like WorldWide Pure Protein shakes. They come in 11-oz cans and you can get them at GNC, Trader Joe's and Fresh & Easy.
I like the chocolate and the cookies 'n cream flavors best, but they also have vanilla, strawberry and banana cream flavors, and I like them all (though I'm not crazy for the strawberry, surprisingly enough).
They have 150 or 170 calories (depends on the flavor), 35 g of protein, and either 2 or 4 carbs (depending on the flavor), 1 g of fat and 1 g of sugar.
Refrigerate, and, when you're ready to use it, shake well and drink over a little ice if possible. They taste quite good, and I still drink at least one every day (usually dividing it up and drinking half in the morning and half later in the day).