The most impactful movie for me to watch has been The Days of Wine and Roses, because it so accurately presents the dichotomy of alcoholism.
Namely, miracles on the one hand and tragedies on the other.
I also like Leaving Las Vegas quite a bit.
Incidentally, Clean and Sober came out a month or 2 before I went into treatment and it played for a good while at the theatre in my neighborhood.
I drove past that marquise everyday, knowing that I desperately needed to be clean and sober and that the whole notion seemed so impossible.
By that point, alcohol had become like water to me.