Well, here's an idea of a line-up regarding the best Juve team of the last 20 years :
------------------------------------------Buffon----------------------------------------------
----------------Thuram------ Scirea-------Kohler-------Cabrini----------------------
-----------------Boniek--------Platini-------Zidane------Nedved--------------------
---------------------------------Rossi----------Del Piero----------------------------------
coach : Lippi
A few remarks...
Zoff quit more than 20 years ago, but I would have taken Buffon anyway for to me he is the most talented goallie of the last 20 years tout court .
Clearly that midfield only works on paper. In reality, a defensive player of the Furino/Deschamps/Davids variety would be essential. I'd personally go for the frenchman.
Although I believe that Laudrup, Vieri and Baggio are better players than Boniek, Rossi and DP, their impact on Juve has been less important than the latter, which is why I did not pick them. Vialli could be a good alternative to Rossi as well.
Thinking of it, making an ideal Juve team of the past 20 years equals merging Trap's Juve (late 70's until mid-80's) with Lippi's first Juve (1994-99, with the exception of Nedved.