Bethesda
Microsoft
Sony
Microsoft had the best presentation by far, surprisingly. Sony had better content but there should be no reason that I have a conference other than Ubisoft and EA on mute for over 10 minutes. I haven't seen Nintendo's, so I'm not including them, but reading an overview gives me no desire to watch it.
Overall, I think Bethesda did the most to further their position with stuff that has their fans buzzing.