Egg White Protein Powder!
Whey protein powder is sourced from dairy, which is not part of The Paleo Diet. Dairy products are the most acid producing items we can ingest and over time, contribute to osteoporosis. (Read: Milk Does NOT do a body good!).
In addition, egg white protein powder has a better amino acid profile than does whey (refer to The Paleo Diet for Athletes chapter on Eating Post-Exercise for a comparison).
If you're making homemade smoothies, or post workout recovery drinks, opt for PLAIN egg white protein powder- it's a no-brainer!