At our November cooking retreat, Chef Lana pointed out that we needed to consider the smoke point of oils/fats.
First off what's a smoke point? "The smoke point of an oil is the temperature at which the oil begins to decompose and visible fumes (smoke) are given off.(4)" Basically heat an oil above this temperature and you burn it and ruin the taste of your dish.
Second - and more importantly - why care? When you're sauteeing and planning on using the pan drippings in a sauce, you want to avoid burning the pan. The lower the smoke point the more likely you'll burn the pan if you're not careful. For example, butter burns more easily than Canola oil. When browning ingredients with a plan to finish the dish in the oven, save the pan over fully browning your meat or veggies. If the pan starts to burn all your hard work is lost. Same with melting butter - if you burn it, toss it out and start over.
As with anything mixing the type of oil or fat for a flavor profile also affects the smoke point. This was important for me as in recipes I always substitute butter with Extra Virgin Olive Oil (EVOO), Earth Balance, or a combination of both. Chef Lana pointed out that the conservative smoke point of EVOO is lower than butter's and should not be heated! (Remember our Chicken with Lemon Caper Sauce? Let's just say there will be a Take 3 based on this new knowledge.)
Go Dairy Free: The Guide and Cookbook for Milk Allergies, Lactose Intolerance, and Casein-Free Living by Alisa Marie Fleming has the most useful charts on which oils/fats to use in what applications (check out the Cooking (and Baking) Oils section on pages 111 - 113). I've listed other online references below.