Another example of a metaphor used so commonly that it isn't a metaphor anymore, but instead a new definition of the word: "a lot," as in "he has a lot of apples."

"Cold war" is an example of what you are looking for, yes. Along the same vein: (see what I did there?) - cold-hearted - hot-tempered - cold-blooded killer - the common cold (used so much its not even a metaphor any more) - have cold feet (nervously reconsider) - left out in the cold (neglected or abandoned) - out cold (unconscious) - hot on the heels (closely behind) - have the hots for (be sexually attracted to) - in hot water (in trouble) There really are too many to provide a list. Those are just the common (American) metaphors that I could think of involving hot/cold in a few minutes. As you noted, there are many, many metaphors people use in their everyday speech without even realizing they are using metaphors.