I've never used peanut oil, but I like cooking with coconut oil a lot and it is probably considered mid-range on its resistance to smoking.
As a general comment about oils from a nerdy chemical engineer...
any oil/fat that is "unsaturated" means that the carbon molecules are not bonded with the maximum number of hydrogen atoms. A "saturated" oil has single carbon-carbon bonds in the oil molecule chain, and the remaining bonds are dedicated to hydrogen. Most all natural oils/fats found in their raw form occur in the saturated state.
This configuration is considered the least reactive. If you wanted to make plastics (polymers), you'd WANT unsaturated molecules to be present, because that makes them more reactive with all sorts of stuff (e.g. oxygen, halogens, or each other). In the case of foods, unsaturated oils/fats are more prone to react IN YOUR BODY, which means you could literally be turning your body into a loosely controlled reactor making funky stuff and not just focused on energy production/digestion.
Take a look at the nutritional info of various oils in your pantry versus coconut or peanut oil. Some oils (especially highly processed ones) have higher percentages of unsaturated fats in them. The food industry "creates" vegetable oils by reacting smaller molecules of light plant oils together (creating a short-chain polymer), then "hydrogenating" them. Hydrogenation is essentially an attempt to make them more like natural oils. Complete hydrogenation would make them look more like fats (the molecules would be heavier, and turn solid at room temperature), so most manufactured oils are "partially hydrogenated", leaving some of the hydrogen atoms out so that the molecules are lighter, and the oil remains a liquid at room temperature. Everybody likes the convenience of pouring their food-grade oils!
The irony is, they could actually make vegetable oil healthier by fully hydrogenating it, but then fewer people would buy it because they'd have to melt it (like coconut oil).
