I haven't watched every conference, but I heard about all the major ones. No clear winner, in my opinion. Each conference had it's ups and downs.
Microsoft definitely had a lot of games to show off, such as MGS: Rising (Although it's not the kind of MGS Sony has, it still makes the Sony fanboys cry their eyes out because they lost one of their once beloved exclusives). Project Natal definitely seems like a plus. Left 4 Dead 2 seems like a bust, it should of been DLC on the original L4D, definitely not a good idea. (Don't get me wrong, I LOVED the original L4D). Crackdown 2, Splinter Cell: Conviction and Alan Wake (About fucking time, Microsoft) are some big exlusives aswell that are added to the 360. Also, new Halo games. Hooray.
EA had a good conference too, from what I seen. I'm not too big into the EA Sports franchises, but APB and Old Republic MMOs seem pretty fucking amazing, especially the Old Republic trailer. Two of them have the potential to be WoW killers. Crysis 2 is gonna be great, too. The Saboteur seems like it has potential, but the theme has been done to death, and I can see it having some flaws when the final copy is released. I wasn't too much into Mass Effect, but I'll probably pick up the sequel to it.
By the way, BRUTAL LEGENDS.
Also, first post for me.