Kagura vs Kamui is another excellent one! Relentlessly physical and relentlessly tough on your emotions.

eta: and yes, I agree! Luffy vs Flamingo is a great example of a FINALLY TAKING THAT BASTARD DOOOOOWN fight.

Another intense hero vs villain fight is Luffy vs Lucci! Like with the Doflamingo one, it's not one where you start to feel for the antagonist, but it's sure got you on your toes the entire time.