While walnut oil technically has a relatively high smoke point, I prefer not to use it for anything close to high heat cooking. It burns very easily, which imparts a slightly bitter taste to the oil and whatever is being cooked. I have, however, used it with some success for low heat sauteing, and in salad dressing.
I think macadamia nut oil has an amazing flavor--all of those fats impart this nice buttery taste. But again, I generally use it for dressings and low heat cooking. Jungle Products
has a really nice product, IMO. They also have what they have termed Paradise Oil, which is combination of coconut, red palm and macadamia nut oils. Very tasty.
For high heat cooking, I mostly use butter, coconut oil or red palm oil.