<div style='font: 14pt Agatha; text-align: left; '>...and in my experience dealing with pre-orders is that you pre-order it so you can have a definate 100% certainty of having it the day it comes out. While it is true that generally anything you can pre-order is going to have about a billion copies available eventually, that may not be true the first 2 or 3 days that it's out. Depending on the product, sometimes that lag between the first shipment and the subsequent shipments is even longer than just the usual 2 or 3 days. Though it isn't a DVD, ask anybody who wanted Diablo 2 the first day it came out how easy it was to find. Or the entire first week for that matter. ~That~ is why store's offer preorders and that's why people take them up on it. To use your Harry Potter example to illustrate this point, for the first 2-3 days here in Albuquerque you were extremely lucky to find it on DVD if you hadn't preordered (there were VHS out the wazoo, but that's not the point.) Now that it's been out a week or so, the DVD is fairly plentiful, but last week it was a pain to find.
In case you're wondering, and I knoooow you are, the 2-3 days I keep mentioning seems to be the normal time to order, ship, and recieve more of a product in retail.</div>
On the warrior's path, only three things are essential: loyalty, duty, and valor. -- Taira Shigesuke"