What are you smoking?

Dear Tricia, Is there a better oil to use for frying as opposed to sauteing? Can I just use olive oil all the time?

Glad you asked, because this is a question that I didn't have to do much research on, which is great because I'm pretty lazy in the morning time.
Canola oil, olive oil, safflower oil... how are you supposed to tell which one is better for cooking? Well the difference between them, besides what plant they come from, is that they all have different "smoking points," which is the point at which the oil burns. Burnt oil smells and tastes like crap, so you want to avoid it. Certain oils are better for frying because they can hold their own against high temperatures, and others just metaphorically curl up in a little ball and surrender like big babies.
So if you're frying, you want to use the following oils, which are the oil equivalent to an American Gladiator: safflower, peanut, soybean, grapeseed, sunflower, corn, canola, or extra light (not extra virgin!) olive oil.
When you're using oil to saute something, you're pretty safe using extra virgin olive oil, sesame oil, or butter.
To dress salads, or use an oil that will stay uncooked, go for an unrefined oils, or something like flaxseed. That's another thing to touch on: unrefined oils. What that means is that the oil isn't filtered to take out the extra flavors and nutrients, which is good for your health, but lowers the smoke point and makes it easier to burn.
Don't ever combine oils. Seriously, if you do, you're just asking for it. It's like when you use sunscreen: you can't combine SPF 20 and SPF 40 and think you're getting a combined SPF 60. So if, for example, you're using unrefined olive oil (which has a low smoke point) mixed with peanut oil (which has a high smoke point) to fry something, its going to burn up pretty quickly because the smoke point for the unrefined olive oil is so low.
Happy Frying, friends!