Either of these 3 options are good as long as they're not electrically conductive. As for the noctua, a lot of people have reported their application only lasting 3 months or so as well while others says their application is still keeping temps low months after use, so if you don't want to take that chance of having to repaste after 3 months then go for the Gelid, it's gotten pretty good reviews itself. (Nice 'The World God Only Knows' profile pic btw).