Here's a few of my favorites..
Champions League:
Zidane vs. Ajax in 97
Nedved vs. Real Madrid in 2003
Del Piero vs. Real Madrid in 2008 at Olimpico (including Amoooori's assist)
Del Piero vs. Monaco in 1998 (both the volley and FK)
Conte vs. Man Utd. in 1999 (for such a long time that goal...