Pacino is way more versatile, IMO. De Niro can do comedy, which is a strike for him, but I think that only works because he is so similiar in most of his films that he can easily do self parody.

He couldn't nail down Pacino like that...

De Niro in Taxi ~Driver and Godfather II were two performances to rival anything Al has done, but taking into acount the range and consistency of all their films its got to be Alfredo Pacino.

Panic in Needle Park, Scarecrow, Godfather II, Serpico, Scent of a Women, Scraface, Carlito's Way, Frankie and Johnny, The Insider, Donnie Brasco, Devils Advocate.

De Niro cant come close to that.
Pacino is the greatest actor ever.