I think most recommendations will say that you should either have the same %'s for fat and protein or less for fat. It depends what theories you buy into, or what works for you
The Zone (which I *think* is similar to south beach--- someone correct me here?)- is 40% carb, 30% protein, 30% fat.
A low carb diet will be anywhere from 10-25% carbs, 40-45% protein, 35-45% fat...
Low fat diets traditionally have higher carbs, proteins in the middle, and of course, low fat.
I think what's important is everything in moderation. I tend to find percents impossible to reach/match most of the time. I am going for as balanced as possible, and staying away from sugars, fatty foods, and high carb items.