I would have to say something that works on auto-pilot. Something that has little or no effort involved. However, that's not likely, so speaking more realistically... I would love to find something that not only highlights my talents, but offers me the ability to help people while doing it. This doesn't have to necessarily be writing either. I use to provide expert advice for many years on liveperson.com and it was rewarding. I had to stop doing it because they were taking too many fees from me!