"What do I put in here?"

Letter in the paper the other day complaining of the use (or misuse as the writer saw it) of inverted commas. As someone who does tend to use them a fair bit, this made me think about just why I do use them. The most obvious use of course (and as far as the writer of the letter is concerned, the only justifiable use) is to indicate reported speech - in other words to clarify that he words inside the inverted commas are not mine, but someone else's. Pace the writer, another use which I would have thought was well enough established, is to indicate a word or phrase which has taken on a special meaning above and beyond the word or words themselves - as for example "credit crunch", "fat cats" and so on. But then, I also tend to use them to highlight words which, despite having a dictionary definition, in general usage may be construed differently by different people - things like the "right" of free speech, and then again to indicate a word which I know is not quite right, but I can't think of a better one. I accept the letter writer's criticism, but inverted commas are so damned useful!