Regarding the biggest club discussion, let's be gracious and give credit where it is due... Real Madrid is the biggest club in football, bar none. So big and successful that even Manchester United and Barcelona have adopted their philosophy of building success (those two clubs may claim that they aren't following Madrid but they still are). Of course though, the circus which has followed Madrid's presidential elections and its impacts on their transfer policy & utilization of their cantera has hurt them. They could have been so far ahead of the rest instead of allowing Barcelona and Manchetser United to narrow the gap. Imagine if Perez had gone through with buying Ronaldinho instead of changing his mind and buying Beckham instead...
Anyway, Juventus is also one of the biggest clubs, but now it has to start acting like it again. I would say that Juventus was the #2 club in Europe, pre-calciopoli. The club has taken a beating since then but the damage can be undone if the club shows consistency. The new stadium is a big step forward.
Here, look at the UEFA coefficients from 1956 onwards. Real Madrid is #1 by a long margin. They have been ranked #1 for 14/53 years. Juventus is 2nd, being ranked as the #1 club for 7/53 years. Then comes Barcelona with 6/53 years, and Bayern Munich with 5/53 years.
http://en.wikipedia.org/wiki/UEFA_coefficient#Top_club_by_period