I usually recommend McCoy plus because the are fairly cheap and almost every LHS carries them. Just as jon2 mentioned, start with a medium plug (Mc 9) and try others if that doesn't run to well.
The one thing to remember about temps of plugs is, they don't actually make your engine run hot or cold. They are more of an ignition timing. A hot plug will run hotter which makes the combustion happen sooner. Then as you get to a Medium to cold plug the combustion happens later. The problem arises when using higher Nitro % and hot plugs you can create Detonation which will ruin your engine.