The general consensus over at Gamespot seems to be MS was the most impressive, followed by Nintendo then Sony.
I was impressed by the Microsoft one. I personally thought the Nintendo one was more interesting, but that's hardly the fault of Microsoft. After all, the poor guys already have a real system with real games on the market and have taken it through one Christmas already, and were talking phase 2 stuff. It's hard to make that as exciting as freaky new stuff that has been kept under raps for over a year now. In any case, what Microsoft was saying was mostly stuff I wanted to hear. They have more intersting games coming, they have more classic games to download, and they've just ensured live is the undisputed online king again. I mean, if I understood correctly, downloading, say, Dig Dug over live gives it to you for a windows diven phone and any computer running Vista as well, and vice versa. Also, earning points on a cell phone or computer game goes towards your Live account (again, if I understood it correctly). Online isn't really my thing, but that does sound pretty cool. For announcements about a product that's already been on the market for awhile, I'd say that's pretty impressive.