At the time of writing this, there are over 1500 comments. I am not going to read them all, nor expect mine to stand out from among the crowd. However, it seems to me that the biggest reason why the US still "clings" to imperial units is because they can. When it comes to markets, they are BIG--even with the recession. When you are the only 800 lbs gorilla in the room and everyone wants to play with you, there are a lot of things you can get away with not doing. As the status of being the only 800 lbs gorilla that everyone wants to play with changes (whether the gorilla goes on a diet, or other gorillas get just as large or larger, or the number of smaller gorillas proliferate to such a degree that the big one is no longer needed, or whatever), then you MIGHT see some changes to metric. Until then, don't count on it, simply because it does not have to do so.