When Twilight Princess came out, the Wii had a userbase of zero. I bought TP for the Gamecube. I imagine millions did. This time, there is only Wii.
And don't quote me on this but I get the feeling that Uncharted 3 isn't going to have quite the same impact as Uncharted 2. Zelda will outsell Drake despite Uncharted's early release.