Kids wanting a console for Chrimbo will get the 360 if the PS3 isnt available.
I reckon most of the "I want/I need... kids/spoilt brats will already have a 360 - they all got one a few months ago - plus the target market for consoles seems to be increasing - people who grew up with atari, NES, master system etc.. are now in thier 20s - 30s
IMO shortage will just increase press coverage on launch and make it a coveted item - so long as it turns out to be ok & the rumours ref performance/overheating etc.. turn out to be false - then a load of people will be after one - plenty of people will also be waiting for a price drop too - so I dont think it will necessarily harm sony if there is a shortage at a launch.
Im in no hurry to upgrade my console - Im pretty happy with my ps2 at the moment but I think I will eventually get a ps3 (though not at launch) - will probably get one when GTA4 comes out - main reason Id like to go for the Ps3 as opposed to the Xbox is for blue ray though tbh..