I have been reading on cooking oils, their uses and our need for fat. We do need good fat; not tons, a reasonable amount. The good fats are the monounsaturated and polyunsaturated fats. The bad stuff is Saturated and Tran fats.
I found an article on MSN with some ideas on how to subsitute good fats for bad.
As for the variety of good oils out there, the book I have been reading says to use the more expensive oils (hazelnut etc) for splashes of flavor on dishes or salad dressings.
Here are some recipes from the woman who wrote the oil book I am reading: