Sunblock, Vitamin D and Cancer

We're told all the time to slather our kids and ourselves in sunblock to avoid certain death from skin cancer. I have not done a ton of research on this, so take it with a grain of salt, but this article and the video it links to are very interesting contradictory information. Think about it - a hundred years ago they had no sunblock. They lived in the sun, working farms, etc. They didn't die from cancers - they died from farm accidents or illnesses like fevers. What's the deal with that?

Now, obviously there is some risk of TOO much sun. We don't want heatstroke and we don't want peeling and blistering sunburns. That would just be stupid. On the other hand, I personally don't want to wear makeup that has sunblock every day or cover my kids in it every time they step outside. We have to have some exposed skin that receives sunshine on it so that our bodies can produce vitamin D. Seriously, it's hard enough to get enough sun here in Colorado because of the cold...