Who delivered the final blow?

[Farael]

But it is more likely that Elendil or Gil-galad gave the most damaging blow or vicious wound, that counted the most to the destruction of Sauron.

Probably, but sticking to the question, which was "who delivered the final blow?" we have to say Isidur.

I don't agree that Sauron was as incapacitated as you think. If Elendil was capable of nearly killing Sauron with a final blow, then why not his son?

Actually, I was aknowledging what others had said. I believe that, while Elendil and Gil-Galad weakened Sauron he still had some fight left on him, until Isidur cut the finger off. Still, I think he might have been at least temporarily incapacitated, as cutting one finger off is not as easy as it sounds :P

I do agree with you that Sauron was drained after making the ring and therefore was forced out of his physical body.