People are stupid, and trying to figure out why morons go to violent extremes for what amounts to an expensive frigging toy has always escaped me. Even when I was a little kid and people were going apeshit and literally killing over those stupid Cabbage Patch Dolls (and more recently those mind numbing Furbies), I just couldn't understand how spoiled some people were, and how their parents pandered to and fueled this insanity.
On the other side of the argument, anyone who thinks that the price of this thing will be half off in 6 months of less is just as delusional as the people spending several months of hard earned money at auction for something that will be readily available withing the next year. Maybe 6 months before the next major revision you'll see it at something close to $300, but not for years at the very least. Heck, it'll be 6 months before the Sony can get their supply to come close to the current demand (as is their decades old M.O. with the Playstation franchise), and that's without factoring in any huge game releases in the near future that would instantly spike the demand over the supply.
Edit - just saw a news report, and most of the shootings and assaults were from scumbags trying to rob people who were online to get the PS3. Although one store did have people waiting across from the entrance in the parking lot, and had them race to the door to claim one of only 10 units when they opened resulting in one serious injury when a kid got flung face first into a flagpole dislocating his shoulder. Without doubt that store is responsible for that kids injury for encouraging a near riot.