Specifically in the Batman The Animated Series iteration.
Sure Bane is menacing and The Joker cunning, but Mr. Freeze has a freeze gun and freezes people with it, what's cooler than that? No pun intended.
http://www.imdb.com/list/_OaGg-zdQKo/
I remember I was super excited for Batman and Robin because this was the first time the character would appear in a live action film, and for what it's worth, it lived up to expectations, I didn't know what puns were then.
http://www.imdb.com/list/_OaGg-zdQKo/
Hey anybody remember when sometimes Mr. Freeze used to be just a head on a robot spider? How does that work anyway?
http://vignette1.wikia.nocookie.net/villains/images/0/0e/Mr._Freeze_spider.jpg/revision/latest?cb=20160430182048
http://www.imdb.com/list/_OaGg-zdQKo/