I'm going to guess that you asked why people are excited about the Wii as opposed to the xbox 360?
My opinion is that while the 360 offers great graphics, a nice online arcade experience with the achievement points and all, downloadable games; the Wii has a control scheme that has sparked a lot of excitement. Why is this so? I am guessing, based on my own opinion, that some people may be tired of the whole "Dual Shock" controller with space marine FPSes/racing games/gta, etc.
Like someone mentioned above, a lot of people just feel that the Xbox 360 is just everything that's been done before but with more polygons and higher-res. textures. Now I have nothing against eye-candy, but paying 300-400 dollars on a system with no games that interest me personally, is not a good investment.
If my opinion can be interpreted to what others are feeling about the wii versus 360/ps3, then there's your answer.