Yeah, I move around like a crazy person, I was told on more than one occasion that I look like I dropped ecstasy before I went on stage. I don't mean to do it, it just happens.

As for whether people should do it, that really just depends. It is definitely more fun/interesting to look at in most cases, but that said some of my favourite musicians (Neil Peart, Mark Hosking) are incredibly stoic when they play and that's also cool in it's own way. Basically, if you are a good enough musician your playing will speak for itself.