Personally I find tags very useful, so I am very serious about choosing them. In fact, I think of tags as emergent in the sense that, given enough people tagging, the output can be bigger than the input.

Given the above, I don't want to tell you how to tag. You know more about your posts than I do after all. And, in general, more tags are better. But I do think there are a few standard tags which would make it easier to locate and group specific kinds of posts.