Wheat Flour

This is the most helpful (easy-to-remember) break-down of flour I've seen.

Whole grain (whole wheat) is what you want. From the description below you can see that white flour has just carbs and is devoid of protein and fiber, whereas whole wheat/grain flour has all 3. You get the carbs too but they are good carbs, plus you get protein and fiber from your bread! Makes eliminating bread from your diet a thing of the past. Canada's Food Guide suggests 5-12 servings of grains daily. For daily energy, complex carbs should make up at least half of your diet.

All-purpose flour is a blended wheat flour with an intermediate gluten level which is marketed as an acceptable compromise for most household baking needs.

In terms of the parts of the grain (the grass seed) used in flour-the endosperm or starchy part, the germ or protein part, and the bran or fiber part-there are three general types of flour.

1. White flour is made from the endosperm only.
2. Whole grain flour is made from the entire grain including bran, endosperm, and germ.
3. A germ flour is made from the endosperm and germ, excluding the bran.

Whole-wheat flour is whole-grain wheat flour.

This is a great site for all sorts of things you want to know:
http://en.wikipedia.org/wiki/Flour