Awesome video. My brother worked on the LRO and sent me a number of the images that it got back from the moon. They have pictures of the original landing site and all of the stuff that was left on the moon. They also synchronized the LRO flight path with the video taken from the original moon landing. It's pretty neat to see everything match up.
Radiation is always a concern with anything sent into space, but they provided adequate shielding on the original lander and in the space suits. Radiation shielding technology hasn't really changed since the 60s. Astronauts get more exposure than most people, but it really isn't that bad as long as their time outside the vehicle isn't too long.
The reasons they quit sending people to the moon was cost, the abandoning of the Saturn V rocket program, and the end of the space race with the USSR. The Space Shuttle program was never intended to go to the moon and was designed to within Earth's immediate orbit.
One thing that has improved since the 60s is robot and sattellite technology. We can get a lot of information with unmanned probes that weren't available when we were sending people to the moon.
As a side note, a lot of the accidents that happened in America (like when the oxygen atmosphere in the capsule ignited on the pad and killed three astronauts, Grissom included) had already happened in the USSR. It's sad that information wasn't exchanged back then, but that was the nature of the time.