It's tough to say, I'd definitely say that Microsoft and Sony were neck and neck. I thought they both had great showings. I love how Microsoft was focused on games, no sales talk etc. I think games wise Sony (Uncharted 2...holy shit) had a better showing, by a hair.
Nintendo was 3rd. They brought a couple big surprises and highly anticipated games, but you had Iwata waxing philosophy...again, Wii Fit 2 boredom, Cammy, bad presentation all around, and a very surprising lack of 3rd party info.
I think Nintendo keeps trying to give a broadly appealing presentation at a largely hardcore audience, and it comes across very poorly, at least on TV. The E3 audience is not where Cammy should be. She should be on Oprah, Good Morning America, Fox News, CNN etc... Putting her in front of the most hardcore gamers, talking WiiFit, is not a good move.
My 2cents on it.