Reason #1 why PS3 is $600. Blu-Ray Capabilities. (That's movies in High-Definition 1080p for those of us less knowledgeable about the subject.)
I saw an advert in this Sunday's Best Buy catalog listing a sole Blu-Ray player (as in not capable of playing video games) selling for $1000, and that's AFTER the $200 price drop.
PS3 is the cheapest Blu-Ray player on the market, so basically, unless you have an HDTV or are planning on getting one soon, PS3 is probably not your console. The prices will not drop for a VERY long while. Xbox 360's prices are the same as they were initially over a year ago now, and they didn't have a built in High Definition movie player.
Also, I have you note that with every PS3 console sold, Sony actually LOSES money. They said that once Blu-Ray technology picks up, the price to manufacture the hardware for Blu-Ray players will go down to current DVD player prices, maybe even less. But as of now, PS3 is the cheapest High Definition player on the market.
Now, since I have a nice and shiny 37" LCD flat-panel HDTV sitting in my living room, it would be worth it for me to buy a PS3. (As soon as I get the $600 needed to pay for it. :P)