I
do hope they will remake the trilogy in my lifetime
. As the Hobbit saying goes, "Third time pays for all", so maybe someone will finally get it right.
So, supposing the creators will have access to a time machine:
Either Greta Garbo or Marlene Dietrich as Galadriel;
Sir Alec Guinness (in his later years) as Gandalf instead of Obi-wan Kenobi. (He once said himself that the similarity between the two was what attracted him to the role in the first place, so why not play the original?)
Hellmut Lange as Aragorn (see
here); but Charlton Heston would be a nice second choice;
Peter Cushing as Denethor;
and last not least...
Klaus Kinski as Gollum!