I find this discussion a little bit difficult to agree with. For the ones saying that its too expensive...if that the case simply don't buy it and use one of the many alternatives that are either free or cost much less. Trying to justify stealing with twisted logic doesn't work.
You may be balking at £500 for CS3 but you don't go stealing a £500 lens nor do you complain about that cost. Many of us here have camera equipment running into thousands of pounds in value and yet equally turn around in the next sentence and say that the cost of software is too expensive for us non professionals
At the end of the day any company can set whatever prices it want to for its products or services, either you pay it and get the goods legally or you don't and make do with alternatives. Anything else is illegal.