The single best exercise for hamstrings is the deadlift and straight leg deadlift. Master that exercise and I promise you will get big and meaty hamstrings.
The key to the exercise is to keep the weight in your heels and drive with your hips. Almost as if you are trying to hump the bar aggressively.
I always use squats as the king of exercises. I agree with Muskate that straight leg deadlifts are also great for hammies. Another thing to remember is that variety in your workouts will only help you.