Finally we can lay this controversy to rest since FIFA producer Tim Tschirner, who has worked on games for both the original Xbox and Wii, has stated that the Wii is about as powerful as the original Xbox. Hopefully this silences the critics who said the original Xbox was more powerful, they're pretty much equal so get over it.
http://www.gamesindustry.biz/content_page.php?aid=25781
FIFA producer Tim Tschirner has said that he believes the Nintendo Wii matches up to the first Xbox in terms of power.
Tschirner's comments came in an exclusive interview with GamesIndustry.biz's sister site, Eurogamer.net
"It's about as powerful as the original Xbox," he said. "The video hardware unfortunately is not as powerful. There's just a couple of key things that you can do on Xbox like shaders which you just cannot do on the Wii... Overall though it's pretty much what the original Xbox was."