>Either way, regular or low fat, you
>will notice slight differences in cookies/baked goods that are made with oil
>rather than butter.

I think the difference bet. the oil and butter is the degree of solidity
when it goes in the oven.  Butter that is creamed into a recipe would give
a puffier product than melted butter added to a recipe.  Do we know if
other oils than olive get solid in the fridge?  I know Canola does not.  I
think working with cold, solid oil and chilled dough would get you the same
or better results than cooking with butter.