Spader's Ultron is, in my opinion, one of the absolute best voice casting decisions ever. Spader absolutely nails the disinterested, calculating, "I really don't care if you live or die but I'll obliterate you for opposing me" attitude of a deadly artificial intelligence hell-bent on eliminating humans. His performance gave me goosebumps in the original movie.

Spader is a great actor, and has been excellent in many things, but this will always be my favorite performance of his.

would be nice if we could do nsfw spoiler tags

This will probably be a one-off appearance in a single episode about Vision reckoning with his origin, struggling with his dual natures, etc, but I'll take it. What I would absolutely love, though, is if Ultron was basically a constant voice in Vis's head, mocking him at every move.