What Exercise Economy means is that there are a handful of exercises that gives you the biggest bang for your buck (look into the Pareto Principle i.e. 80 percent of your results will be from 20 percent of your effort). Could the best exercise for you be the Deadlift? Possibly. The Thruster? Good choice as well. Kettlebell Swing? Maybe.
Part of what you need to think about when you look into Exercise Economy is the number of exercises you perform. Do you do a lot of "stuff" or are you doing core exercises that are going to benefit you across all of your athletic needs? I can honestly say that we stay within a pretty narrow band of body weight, bar and kettlebell techniques - and exercise economy is the reason why!
NOTE: check out this great podcast by Gray Cook talking about Exercise Economy. It's about ten minutes long and I'm sure his thoughts on this matter will spur you to make changes in your training program.