about Agave

Note if you've read the bad press agave has been getting lately, here's a link to a response by Craig Gerbore, President of Madhava (the major producer of agave)  http://alteredplates.blogspot.com/2008/12/madhavas-craig-gerbore-responds-to.html
this article is quite comprehensive and responds to the issues that generally concern home cooks about agave.

Agave is sweeter than sugar, so you can use less.  It has a low glycemic index, about 30 (see below for comparison to other sweeteners.  Agave contains Inulin, a prebiotic fiber which promotes healthy function of the lower intestine.  There are also studies which have shown that Inulin promotes regularity, boosts the immune system and calcium absorption and increases bone density. 

There is light and dark agave available, I have not found much difference in the taste, so I use them both.
Cooking with Agave:
Agave is about 1.5 times sweeter than sugar so the amount added to your recipe is about 1/2 - 2/3 cup agave to each cup of sugar called for.  Agave acts as a natural preservative because it retains moisture, baked goods will stay fresh longer.  When converting a recipe from sugar to agave, you may want to decrease the other liquids in the recipe – for instance the amount of oil can be reduced by a third (if 1 cup is called for, reduce to 2/3 cup).  However, I have found that this process very forgiving, sometimes I reduce the liquid, sometimes, I don’t – it always turns out wonderful. 
Liquid sweeteners such as honey and maple syrup can be replaced with agave in equal amounts.
To start experimenting for yourself replace each cup of white sugar in your recipe with 2/3 cup agave and reduce other liquids by ¼ to ½ cup.
For each cup of brown sugar, use 2/3 cup agave and reduce other liquids by ¼ cup.  Liquids do not need to be reduced as much as white sugar because brown sugar has more moisture.  And, depending on your recipe, liquids may not need to be reduced at all.

My experience with agave has been very positive.  I have converted several cake and quick bread, muffin recipes to agave instead of white sugar and brown sugar.  If you are interested in trying out agave, use half and half (substitute ½ the sugar in your recipe for agave).  Because agave retains moisture, I think it improves the texture of many baked goods. 
However, I must add a caveat for cookies.  Cookies like Chocolate Chip or Oatmeal depend on the sugars for the quality of the texture.  My experience with agave here has not been 100% positive – but I don’t make too many cookies, so I’m still experimenting.
Sweetener Comparison Chart
Item
Fructose
Glucose
Total Sugar***
Calories per 100 grams
Glycemic Index
Table Sugar*
50%
50%
97%
500
58-65
Honey
38 to 42%
35 to 40%
80 to 84%
304
46-83
Date Paste**
32%
34%
70 to 80%
270
103
HFCS
55 to 90%
45 to 10%
100%
370
62
Agave
49%
17%
64%
308
30


The glycemic index indicates how quickly the carbohydrates in foods are converted to sugar.  Foods which rate a high glycemic index (glucose is given an arbitrary rating of 100 and all other foods are measured relative to that) are foods whose carbohydrates digest very quickly and raise the blood sugar immediately.  The fewer easily-digested sugars and starches a food contains, the less likely it is to create a spike in blood sugar.