I would think using things like musical publications reviews is a better gauge of a band/ act's talent in their field. Using sales or something like the Grammy's will just lead you to look at the billboard sales chart and determine the "best" act in a genre is the one who sold the most or who exploded on the scene the loudest. At least people who review music for a living are a slightly better judge of talent in a genre that they have or even groups of musical historians that can look back and come to some type of group conclusion. Of course in the end it means nothing because judging art or music is all about personal preference and anybody who disagrees is basically envoking their inner 4 year old and telling others what they like is not good. The debate at SOSH on Bill Simmons and the how to judge something based on what said thing is trying to accomplish is really the crux here. I'm sure you can safely say that Jay-Z has been one of the best at accomplishing what he set out to accomplish. You may dislike the music, but that simple fact is hard to argue.

Like I said, I have no feelings on the matter of Jay-Z's musical exploits or talent, to be as successful as he has been he's obviously got immense talent, I just thought using the Grammy's was a bit odd there.