It is confusing, isn't it? When you ask 100 people that question you will probably get 100 different answers. I read an interesting article the other day that suggested that our need for carbs changes from our 20's, 30's, 40's. In other words, in your 40's and 50's, you don't need the carbs for energy that you do in your 20's and 30's when your chasing after little ones, etc.
Another article suggested that the type of diet that's right for you depends on whether your an "apple" or a "pear". Here's the link.
Body Shape - Apples and Pears
As for me, I try to keep my carbs under 50%. But that's just my preference.
Hope this helps a little.