I would like to see one of our past hero taking over the job if Lippi leaves. Anyway, I can see Ciro or Conte, the former being more likely, being given coaching, and assistant role and eventually take over the team.
My favorite list: Gentile, Deschamp, Prandelli, Ferrara,
Capable replacements: Irueta, Porto Coach, De Canio (Still relatively young and extremely good tactician. He also seems to be a very good man, remember Fiore goal celebration?), Sammer.
Ok list: Vialli (I was fan of him during his playing days, and Vialli's leadership quality is undoubted but he never impressed me with his tactical ability. He is more heart than brain), Conte, Baggio

, Wenger, Rafa Benitez.