1. Blade Runner (1982)
2. A.I. (2001)
3. Her (2013)
4. Minority Report (2002)
5. Ex Machina (2014)

There are some movies with an AI character or element in them that are better than some of the ones on my list, but they are not really about AI. For example, The Matrix or Alien. Prometheus might fit a bit better than Alien tho (and I love that movie, fight me).

And there's also Minority Report, which doesn't directly have an AI, at least not a clearly defined and prominent one. But if you forget about the precogs, what's left is a pretty prophetic world where algorithms rule society, not only to tell you what to buy, but also to put you in jail even before you commit any crime. It's scary how close we are getting there, and this comes from a 2002 movie based on a 1956 book. More ML than AI, but whatever, it's my list.

Two movies that didn't make it into the list by a whisker were Westworld and The Iron Giant. I probably like The Iron Giant more than I like Ex Machina, but Ex Machina is more on theme, so there's that.