Best summary I have seen on the topic. Deadlift vs Squat – Comparing Strength and Muscles Worked
It is clear that it is worth doing both, but not on the same day. For what it's worth, I do back squats once weekly, deads once weekly, and leg press once weekly for lower body resistance exercises.
It is difficult and slow to build lower body power with my particular physical architecture (runner's build), but I work at it. Just increasing the wts by 5 lbs/month is great.