It's a big call I know but if you were to ask most trainers they would unreservedly vote the squat the best exercise going around. But why?
For starters it's a movement and not an exercise. What I mean by that is many of the exercises people do in gyms are manufactured movements designed to specifically target certain muscles. This doesn't work because our muscles never work in isolation in life, so why train them that way? A movement on the other hand mimics life's demands while at the same time works groups of muscles in concert. It provides a better work-out and get's you life ready.