Wii will sell the most. Price Point attractive repackagings. 3rd party support snowballs into 08-09
MS will make a ton of money if they hold off on a price drop, and build the perceived value till after 07 holiday. They don't have to rush, as PS3 isn't really direct competition either (see below). Online gaming will reach its peak in innovation (think 360 is to online what SNES was for 2d sidescrollers, fighters, etc).
PS3 will start to pick up by holiday 08 as Blu-ray movie library increase and HDTV are more common in homes. More games will feature 1080p, and this will attract the hardcore gamer back to sony. Sony online will have some interesting features, like Home and a more refined Camera. Sony will begin "buying" exclusives later in the gen.
Three different products for three different gaming purposes. Second and Third place will be bigger than last gen, but Wii will just keep selling like crazy.
A little more crazy prediction/hope - Low powered Wii may see a sub to par -360 successor in 2-4 years, sony and MS would then delay the release of their next gen to recoup losses from the early part of this generation. We really could see a 7-10 year cycle this time around. I hope for this because although I like graphics, they just aren't increasing enough to warrant another generation of consoles (from a business stand point). If the arms race continues too heavily, the whole industry might suffer.
I would cite regulation, but I know you will simply ignore it.
