Just saw Molly's Game last week, very good movie. Now, it is not exactly a movie about poker but it does revolve around it and there is poker involved, meaning there are poker scenes (good ones), so I have to say Rounders now has become my second favorite movie about poker since this one gets the first place (for now, I hope).
It is based on the true story of Molly Bloom, BTW. I searched about the true story behind it, after watching it of course (didn't want to spoil it for me, since I had absolutely no idea about the true story before watching it - didn't even know it was based on one) and found out about some interesting "funny" real stories. I recommend watching the movie first, otherwise it will affect your movie watching experience, and wtaching the movie is a lot better than the stories.