I use the CytoSport 100% whey chocolate powder. I get mine from Costco,
6 lbs for just under $40, only 130 calories. It is a little too sweet for me so I add 1.5 cups water, more filling that way

No bad aftertaste.
I tried the vanilla Designer Whey a few years ago and hated it due to some kind of weird aftertaste I now associate with protein drinks.
Be careful of the protein powders that contain high calories.