Look, how about I chuck a spanner in the works and work out what defines 'graphics'. Id say mario Galaxy has some of the best graphics I've ever seen. Whilst not realistic, it has a very appealing 'graphic' look. Its pushing some nice effects and has some awesome variation to its levels that keep you saying 'wow!' at every turn. However it isnt pushing as many polygons or resolution as The Other Two, it surely has some 'nice graphics'. If Mario Galaxy is a look into the future I'm sure we can expect some prettier Wii games in the future, not as nice as 360 and PS3, but they can surely stand on their own.
And as I always say, graphics arent everything. Surely a woman can be attractive, but that doesnt mean she'll be good in bed ...think about it