I eat a LOT of salt. (celtic or other unrefined sea salt now. before, standard table salt, before I learned that it wasn't as healthy). I have to. like many other posters here, if I don't eat enough salt, I get extremely low blood pressure, and black out when I stand up. (Not enough to fall down or lose conciousness, but totally black vision for 30 seconds or more, and dizzy). One doctor suggusted increasing salt intake, and it REALLY makes a difference. When I eat a lot of salt, I don't black out. (dehydration is also problematic, but the salt and proper hydration are key).
I do think that most americans probably get excess sodium in their diets from processed foods, but I don't think its likely the healthiest form of sodium. I think people would be better off salting their food to taste with homemade food (but thats for reasons not just salt.)
without highly salted processed foods, I think that salt is a vital addition to the diet.
I also think that the body helps you know how much salt you need. Food will taste properly salted for you depending on how much salt you need. If you need more, you will like a saltier taste, and vice versus.