I think that, despite the Wii's success, it's all going to boil down to the software. Until Gears of War came out, the 360 was basically the run of the mill system. Oblivion wore itself out, Madden and NCAA were jokes, and despite good ratings, Ubisoft games weren't that great.
Here's where it stands.
The Wii has Zelda. Mario Galaxy, the new Smash Brothers, basically 1st party games that will either take it to the next level or basically end Nintendo's run at a serious console manufacturer. Sorry to be harsh but the N64 and GC prove that Nintendo has lost its edge. They are obviously great in the handheld segment, as the GBA, now DS rock every month with high sales and equally great software. The DS shows that its not always about the graphics.
The PS3 is a shot in the dark. Pushing both a new and unique chipset and an unproven successor to the DVD throne, they have a lot to lose... because the cell and the Blu-ray ties into a vast portion of Sony's future stock in electronics. Cell powered LCDs, cheap Blu-ray players for the masses, the stake here is a lot higher. Obviously, they've fumbled numerously with Kutaragi failing to secure exclusive titles (Assassin's Creed, GTA) and the damage at a late launch of the PS3 can't readily or easily be measured in lost sales against the 360, Wii, or what other franchises they've lost or are about to lose. But where the PS3 will succeed is in bringing so much more functionality to an already great system. Yeah, realistically, its not exactly on par with the 360. But the potential is there. You see it with the XMB, the playstation store (I hate that blue thing) and in that you have some options that the 360 doesn't have like web browsing and a built-in High Def DVD player. But again, software is going to be the big breaker for Sony. Whatever franchises they have left, if I were Hirai, I would be very personal and hard about producing quality titles from here on out. Don't give me a Madden that is a little better polished than the 360 version. I want my titles to stand out. Why should I buy a PS3 title that'll look just as good AND is the same game that will be released on the 360?
The 360... bleh. XBL is great and tagged with GoW and Halo 3, is the only reason why I'd keep one. The 360 launch was HORRIBLE and the only game worth playing at the time was COD2... with a honorary mention to PGR3.
IBM is the big winner here. All three consoles are powered by an IBM design chip, save the cell, which is an IBM/Toshiba/Sony project. But if they make (hypothetically) 10 bucks per processor on all three systems, DAMN.