Gene hackman would be my first choice I loved his portrayal in the first two movies.
Kevin Spacey was really god too a little darker.
I really enjoy Michael Rosenbaums version but he get's to work it better because of the run of the show.
Lyle Talbot was really good in the Seriel very Golden age Luthor
and Clancey Browns version I love his voice is what I hear when I read a story with Luthor in it.