To people claiming the Wii has peaked already..
I HIGHLY doubt the most successful console of all time has peaked in only its 2nd year when most consoles generally peak in their third.. Keep in mind the Wii doesn't quite work in the same patterns as most consoles because it appeals largely to the expanded audience, which are a huge wildcard.
Also keep in mind that the Wii has yet to release its 3 biggest bomb shells possibly in its lifetime; NSMB Wii, DQ X (in Japan), and a true ground up Zelda for Wii. And this doesn't even take into account the x factor of the Wii series, which Nintendo could churn out another hugely successful "Wii" game out of the blue.
Wii may have very well reached its peak I guess, I'm not saying that for sure that it hasn't necessarily, but the important thing to look for is LONGEVITY of sales, and in that regard I think Wii will outlast its competition, just as many of its games tend to have greater legs than their HD counterparts. If the Wii peaked already but maintains these sales or with a minimal drop over the next few year, than isn't when it "peaked" largely irrelevant? Sure it's sales are down from last year, but that is mainly because it sold so abnormally WELL last year, not necesarilly that it's performing badly this year.