Protein drinks sometimes give me gas. Dillution (more water) can usually help with this. Also it's an easy way to up your water intake.
I like adding ground flax seed to my shakes. Two tablespoons will add 3 grams of ALA (a type of Omega 3 fatty acid), 3 grams of protein and 3 grams of fiber. The ground seed has a very mild nutty flavor which doesn't really disrupt the taste for me. Oats is another easy option too.
Pure whey drinks are notorious for spiking insulin levels and leaving you hungry. This is why I prefer a whey/casein blend like Metabolic Drive. Save the ON whey for mixing with food, like oatmeal and yogurt, and use Metabolic Drive when you want a protein drink.