Squats are the most effective leg exercise bar none and you need to realize this. No other exercise even comes close. And not only does squatting build big strong legs it also increases overall body strength and size. You literally use every muscle in your body when you are squatting.
Squats are the toughest, most intimidating exercise you can do. Because of this, people will dream up any excuse imaginable to avoid them. Don't fall into this trap. My advise is for you to learn to love squats. I have never seen anyone with outstanding leg development where squats was not the cornerstone of their leg training.
Make sure you learn to squat correctly. Start off light and get the proper form down. Get very comfortable with the full movement. By learning the proper execution of the squat you'll be more comfortable as you increase the weight. Poor form and heavy weight in the squat is not a good or safe combination. Take the time to learn to squat right and it will pay big dividends down the road – not only in leg size and strength, but you'll see size and strength improvements in every muscle group.
I've said it before, if you don't incorporate heavy squats into your training program your not serious about your training.