The 360 needs to unload some hot titles to maintain their console lead over Nintendo. The Wii is constantly selling out due to reputation alone.
It doesn't hurt that Zelda: TP is the "game of the year" in several categories.
The PS3 has Virtua Fighter 5 and Motostorm on the way.
The Wii has Wii Play and Mario Party 8.
I have a feeling the novelty of the system will wear thin sooner than later.