Even tho I like Pacino more, I agree that both Pacino and DeNiro are brilliant. While it's hard to pick a favorite role for each outside of the GF, I must say I loved Pacino's performance in Dog Day Afternoon and I thought DeNiro in Cape Fear was magnificent.
"Mankind must put an end to war before war puts an end to mankind. War will exist until that distant day when the conscientious objector enjoys the same reputation and prestige that the warrior does today." JFK
While it's hard to pick a favorite role for each outside of the GF, I must say I loved Pacino's performance in Dog Day Afternoon and I thought DeNiro in Cape Fear was magnificent. 
