I love using it in shakes! I currently make a shake with PB2, a banana, and strawberry banana yogurt. I usually put 2-3 tablespoons of dry PB2, pour a little bit of water in and mix it up. It's tastes HEAVENLY.
Be warned though, with that much PB2, it overpowers the other stuff. I love the taste of peanut butter though, so that's what I'm looking for
If you want just a hint of it, you can probably go with just a tablespoon or even a half.
I've been trying to find recipes for peanut butter cookies (or create my own) that use very little sugar. I'll have to get back to you on that once I try making them