I use whey powder by EAS. It has 20 grams of protein, 5 carbs.
I put good old h20 in it, a frozen unsweetened strawberry or two, and 1/4 c. of 1% cott. cheese, an ice cube, and 1 pkt of splenda.
It's pretty good and not high in carbs or fat. If it's just after a workout I skip the cott. cheese...