Flour

[Lalanae]

I'm looking to start substituting different flours for wheat flour in homemade goods. Anyone know much about different types of flours (rice, soy, buckwheat) and how they work best in baking? Basically what I am looking for is:

If I'm baking, what is the most nutritional flour to use? Will it work better for some baked goods than others (texture, lightness, taste, etc)? And any other tips you may have about using particular flours...

[Truant]

A few things.
Baking with flour other than wheat becomes tricky because the gluten in wheat flour is what allows air to be trapped in the dough (in the case of bread), giving you nice fluffly bread, cake, etc. Other flours (like the ones you mentioned) are gluten free which would produce extremely dense and non-risen doughs/products. For other baked things like pastries, the gluten is what helps to hold the dough together, and without it things fall into a pile of crumbs. You get around this with gluten substitutes, some work better for bread types, others better for pastry types.
As far as nutritional value, I honestly don't know excepting soy flour, which has some fat content.
As for applications (and gluten substitutions) I found this link for you http://allrecipes.com/HowTo/Using-Alter ... etail.aspx as I'm not super knowledgable about all this. It seemed awesomely informative.
My patience for baking does not extend past bread tbh so I'm not a whole lot of help for other types of baked goods. I do however have some pretty serious bakers in the family I can ask if you'd like!

[Sabek]

The thing you run into when you move away from wheat flour, which I have to do now, is that you can not simply say x cups of wheat flour = x cups of some other flour. Generally you have to mix several types of flour to get the same results.
I generally use brown rice flour with tapioca flour.
As was mentioned you will need something to replace the "structure" that the gluten provides. Normally that is Xanthan Gum.

As far as nutritionally I can really tell you, because I am doing it for health reasons.

A good place to start is any of the gluten-free cookbooks available out there.
Anything by, I believe, Bette Hageman is a good resource.