Actors who you just can picture anybody else in that role

I was reading about how about how the original Aragorn from LOTR was Stuart Townsend and got fired pretty quickly and replaced with Viggo Mortensen. Good pick IMO that would've been a disaster and I thought Viggo was awesome in that role to the point where I really couldn't see anybody else doing it better. It got me thinking some characters just belong to that actor, they own it.

Denzel Washington in Remember the Titans. Came in with so much soul, he's got this rhythm in the way he moves and talks that really adds to it but I think this was the best thing he did and he's done a ton of great stuff.

Kelsey Grammar as Frazier Crane in Frasier/Cheers. He just has a way about him that just so fucking funny. So different too.

Harrison Ford as Han Solo. Especially for it's time he just had this cocky charisma that made Han Solo one of the greatest characters in Hollywood history.