I use some form of squats with all of my clients because I KNOW that they can change your life and make you a healthier and happier individual. This variation is called The Goblet Squat because you hold the weight as if it were a Goblet in your hand.
Although the barbell back squat will always be king, the Goblet squat is nothing to sneeze at. It's extremely effective even with minimal weight! Great for if you've only got a hotel gym to work with!
I like the Goblet squat because it teaches people to keep the weight in your center of gravity and allows you to really sink LOW in your squats. If you're a beginner you can see tremendous development in your legs and butt with this as your primary leg exercise. If you're Advanced, this is an amazing accessory/hypertrophy movement to help your legs grow and also grow stronger!