Olive (and especially extra virgin olive) oil is going to give your food a relative flavor that you would not get with vegetable oil or canola. The thing is, you lose a lot of the flavor when frying or sautéing, so it's a very subtle difference. If the slight addition of flavor from the olive oil is important to you, then use olive oil. If not, you might as well go with basic oil. One other important thing to consider when choosing an oil is its ability to withstand (or not) certain levels of heat. Watch this video to learn the difference in smoking point between oils and butter. http://how2heroes.com/videos/techniques/cooking-with-oil-vs-butter . If you're cooking at a high heat, canola oil is better than olive oil or butter.