I have nothing against it, I actually did it with the 360. My friend worked in a game/CD/DVD store and had one pre-ordered the second such a thing became available to him. Now it had always been his intention to buy it, but when the day finally came he found he just couldn't make his finances stretch enough, so after noticing a huge amount of 360's on Ebay selling for double their RRP he allowed me to buy his pre-order and do with it what I pleased. So I bought it with his staff discount for something like £260
I took a gamble, a exchange store was offering somethng like £350 for the 360's and I'd seen some on Ebay go for less than that, but I put it on Ebay and I guess I won, I got £620 (approx 1170 US$) for it, from someone local so we didn't even have to bother with shipping. The man who bought it had been asked by his boss to go and find one for his son at any cost. Some people just have more money than sense, and I'll be glad to take it off them. So I made a very nice little turn over just in time for Christmas, little Jimmy got his Xbox, the guy who bought it got praised from his boss and everyone was happy, except my friend because he'd really wanted to play on it but I wouldn't let him.
I've had a Wii pre-ordered for like 6 months, but I have no intention of selling it on. Why? I think there will be a shortage, but not nearly as much as Xbox or PS3 so I don't think I'd make that much from it, also the Wii will just rock way too much for me to even want to sell it, i'm getting it and I'm playing it all damn day.
In my opinion if you really want something, you should've pre-ordered it. They're not 'taking it away' from you, they're actually helping you by offering you the chance to buy a console that you otherwise wouldn't get in time for Christmas because you were too stupid to pre-order it, knowing the sorts of stock problems these console always have at launch. ('you' does not reffer to anyone inparticular, I'm just using it as a generic).