I was listening to the Boogie Nights commentary last week and was consistently shocked and surprised at how thoughtful and interesting Paul Thomas Anderson's insights into the filming were. Lots of different stories and reflective thoughts about filming and story-telling. I was impressed.

I listen to a lot of commentary because I'm weird in that I like to fall asleep to people talking sometimes...but sometimes they're so intriguing that I have to revisit them the next day and listen to them in full.

Francis Ford Coppola's commentary on Apocalypse Now is also very interesting and worth the time to listen to.