I love PTA's Boogie Nights one as cliche as it sounds. It's the best commentary I've ever heard by one person alone. I love hearing all the influences and references and funny stories. Those are what commentaries are all about, that's the way they should all be.
Kevin Smith's are all great. I could listen to him and Affleck all day. They are perfect together, so damn funny.
Cameron Crowe and his mom's Almost Famous Untitled one is pretty great. It's always great to hear a commentary of such a personal film.
David Gordon Green and Paul Schneider's George Washington commentary is one of the best ones of recent. They seem like two really cool guys, definitely talented too.
There aren't too many others that I can really think of. Wes Anderson's Tenenbaums one is cool. I need to listen to more. I've been checking out your guy's picks.