If the Wii can get a good selection of "core" game titles to add to it's "non-core" collection, the Wii might be able to close the gap a bit, at best, in the 4th Quarter of this year. The Wii will, at best, be moderately behind on the "core" level because of Halo 3 and GTA IV, but if Nintendo can get either of their big "core" games, Metroid Prime 3 or Super Smash Brothers Brawl, then it can probably throw off some of the 360's "core" momentum, but definitely not all of it. I admit odds are iffy-poor though, because of the big selection of core titles for 360. Where the Wii will blow right by the 360 is the "non-core" category, if they can keep the momentum up in that end, I can see the Wii pulling a bit ahead in the holiday season, best case scenario, but anything more I think is unrealistic. The big questions will be momentum with the games, hardware production, and online. Those are both the serious factors that will determine how well the Wii compares to the 360 this holiday season. Post holiday season is way too hard to guess, I'm not really aware of many planned titles for either platform past Christmas. Speaking of online, we know it goes through Gamespy, but they haven't been exactly clear on how the code system will work. And toss into the mix that the company that made Xfire (pc game-chat program) has indirectly acknowledged that they're working with Nintendo. The Wii may end up being a big flop online, however we won't start to have any idea what direction they're taking until May 25th, methinks, when Mario Soccer Wii launches in Europe (online title). Personally one of my most anticipated titles is Fire Emblem Wii. :) Btw, I'm only referring to North America.
Nobody is crazy enough to accuse me of being sane.