I haven't listened to everything but you should check out the commentaries with Sendhil Ramamurthy, Zach Quinto, Greg Grunberg and/or Jack Coleman. As far as I remember the Milo/Greg Grunberg was good, too. But Zach Quinto and Milo was boring because they are both rather silent people. However, Zach Quinto/Sendhil Ramamurthy was great, same goes for Sendhil Ramamurthy/Greg Grunberg.