Fluoride - Good or bad?

So.. I know this is probably just going to open up a can of worms, but I was trying to seek some information regarding the safety of using fluoride.

Right now, my family and myself all use Crest or Colgate toothpaste, which is loaded up with fluoride. But recently, I've been told about how bad fluoride can be for your health, if used constantly and excessively. How true is this and how much should I be worried?

This article about the dangers of fluoride talks about why it's bad for you, but does not offer any sort of tips to avoid it or a product I can use instead of the mainstream toothpaste. Can anybody recommend a toothpaste that is fluoride-free, but will still freshen my breath and fight cavities? Any help would be appreciated. Thanks!