Here is a BBC episode (30 minutes) about the life of Sagan and about his influence on a whole generation of scientists. In particular, physicist Brian Cox talks about his life-changing experience after watching Cosmos as a 13 year old. Well...he is definitely not alone in this experience. Cosmos aired in Pakistan in 1984 and I was in my 9th grade at the time. Going in, I did know what to expect from the show and was not really excited to sit through a documentary. But by the end of the first episode, especially after the Cosmic Calendar, I knew I wanted to be an astronomer. The following week, I remember explaining the Calendar, unsolicited, to anyone and everyone I met (yes, this may have gotten a bit annoying :)). Sixteen years later, I got a PhD. in astronomy (damn - it takes a long time!). However, it is not just astronomy. Sagan also imparted a sense of wonder about the history of science, and science, in general. It is amazing, however, that I never met the guy who altered my life so dramatically and then from a program made thousands of miles away and living in another culture.
Rest assured, there are many astronomers today who will tell you a similar story about Cosmos and its life-altering experience.
Listen to the BBC show here. Also here is the bit about the Cosmic Calendar: