My vote goes to "Mean Streets," Keitel's most interesting and nuanced role--a perfect counterpart to DeNiro in one of DeNiro's greatest roles. All the others in this video were good. I would have loved to have seen him do more in "The Irishman"--he was great as Angelo Bruno in that brief scene in the restaurant where he tells Sheeran (DiNero) that he burned down a laundry owned by Bruno.
Imagine what he'd have done in "Apocalypse Now" if he hadn't been summarily yanked and replaced by Martin Sheen (who was excellent).
Ntra la porta tua lu sangu � sparsu, E nun me mporta si ce muoru accisu... E s'iddu muoru e vaju mparadisu Si nun ce truovo a ttia, mancu ce trasu.