People were paying upwards of $1000 on ebay at the time that the Xbox 360 launched, and it still doesn't have any games that I want to play. I was really interested in getting the 360 because it looks and sounds awesome, but there's just nothing that I feel like playing on that system that I can't get for PC!
I think this is a battle between the Wii and the PS3. Sony just has better exclusive games. The PS3 is the most high-tech of all 3 systems, and it's the only one that comes with a blue-ray player. It's pricey, but I doubt sales are going to suffer much considering the hardware in the box. A blue-ray player alone is probably not going to be much cheaper than the PS3.
The Wii has that freaky controller (a plus in my opinion, moving away from tradition). And it's Nintendo. They'll have some fun titles. And it's going to be very cheap. Nuff said
The 360 really has nothing going for it except an early launch. It has very few exclusive titles, of which there aren't many good games (I'm not a Halo fan). I'm sorry, but there's just nothing there.
In the end, I think the Wii might sell the most units because it's just so damn affordable, followed by the PS3. Hopefully the list some additional "extras" that the premium PS3 model will come with, if any.