Spak: 500,000-700,000 is half of what Nintendo was saying in September. I heard 1 million on launch day up until now, plus 1 million more by the end of the year. *worries*
The price of PS3 won't matter as long as it's in such short supply. People are paying $2000 for them on Ebay. Until the system is easy to get I don't think we'll really know what effect the cost has. But supply issues are still a big problem - if Sony only reaches say, 3 million by March, publishers planning their 2007 releases will have to seriously consider how many customers will be able to buy their games on PS3.
Edit: Can't spell Septebmer.