I want mine with no redemption. Gimme a good-old bad guy.
I like the old-school “try to take over the world – just because I want to” villains, and have been bothered by the number of “the world should end because the world let my daughter die and I’m so depressed” pseudo-villains that have become more common.
Take note though (definitions are important), an antagonist is different. In several of my favorite stories the Protagonist and Antagonist resolve their issues near the end of the story and work together to defeat a real nemesis. Sometimes the evil one can be an antagonist (or in some cases even a protagonist, while the hero working on the side of good is the antagonist), but that doesn’t change what their motivation should be: true evil.
It’s fiction, after all, and it doesn’t have to be realistically complicated with moral ambiguity. Just my preference.