Best oil to use for stir fry ?
Peanut oil is a good choice because of its high smoking point. Do not use if you have peanut allergies...
It's best to use something with a high smoke point so you can get your wok really hot without burning the oil -- peanut, especially, but also canola, coconut and grapeseed oil are good choices.
I usually use peanut oil, but sometimes grapeseed.
Coconut oil is great but can have a distinct flavor & aroma of its own (BTW, it pairs great with plantain), peanut oil would be my first suggestion.
I usually use sesame oil because of the great flavor it lends the dish. I believe it has a slightly lower smoke point than peanut oil, but it's not too far off. I've never caught it on fire, anyway (yet).
Agree with peanut oil comments (it also adds an authentically Asian flavor). But that grapeseed oil is a close runner up. I sometimes add a small amount of chili oil to the former (that combines soybean oil with chili powder---makes you strong).