Due to Nintendo's reputation for quality materials and building. Not only that, but it'll be the cheapest. Those are the biggest deciding factors for me.
Hmm, they still have that reputation, yes. I do think it got bashed quite a bit with the Gamecube though. I've got one, and well, it's okay. I think it's fair to say that the Gamecube is the least of the last-gen consoles. It didn't have the graphic power of the Xbox, nor the line-up of the PS2. And, more importantly, it lacked the reason why Nintendo does not have to make a super-graphics console: names. Zelda, Mario, Metroid etc. Sure, there were some, but not that many. And when we look at the third party games for the Cube, there are in comparison to both the Xbox and the PS2, "few".
Nintendo has, IMHO, not lost it's touch and credibility though since they have always tried to "make the best" out of the Cube, even though it wasn't that big of a succes. (In Japan it was.) And the few titles which were there were absolutely great: "The Wind-Waker", "Metroid Prima 1&2".
So, a Wii it is for me as well. And I've got good faith in Nintendo.