games - right now Nintendo is looking like the winner here, with great franchise games promised for launch. 360 had a pretty impressive launch lineup, but a lot of the better games weren't released until later. PS3 right now has a very unimpressive lineup, especially when you consider the $500 pricetag.
hype - 360 and PS3 will win this, 360 did a great job of getting everyone into a frenzy for launch day. Sony will look to do this too, price tag's gonna hurt it though. Don't look for the same amount of hype from Nintendo though, they haven't done it for the past two systems and I don't see them changing their ways with Wii.
power - PS3/360, with Nintendo trailing the pack, going for innovation over power.
availability - Nintendo will most not make a big deal about availability. We all know what 360's availability was like, look for the same from Sony to help drive hype and get consumers into a frenzy, so they have to get one at launch.
Overall, I think Nintendo should have the most impressive launch, but won't. Sony will use the tactics 360 and PS2 used to work everyone into a frenzy to get a system that will have a very weak launch lineup. Realistically, I see it being 360, PS3, Wii, while I think it should be Wii, 360, PS3