Unfortunately, I didn't get to see everything today. However, here are the overall first impressions based on what I saw:

Sega of America - Sonic Generations looks promising to say the least, with it's new-school meets old-school style of gameplay. Their preview of Gearbox's upcoming Aliens: Colonial Marines was highly impressive, showcasing some of their gameplay mechanics and multiplayer. I got to demo an overhead dual-analog shooter (the name eludes me) that they will be releasing on PSN, Steam, and XBLA and I had a blast trying it out. I was a little bummed when I heard there was nothing on the new Phantasy Star games, but aside from that, they're a personal favorite.

Square-Enix - They seem to be getting their act together this year. While they announced Final Fantasy XIII-2, it wasn't the main focus of their booth, as I saw demos of Deus-Ex 3, Dead Island, along with another game (again the name eludes me). Unfortunately, no news on upcoming Dragon Quest games coming stateside.

Konami - Konami had a pretty huge booth. They were showcasing the new Silent Hill: Downpour, which doesn't look too bad. Metal Gear Solid 3D, which is their port of MGS3, to the 3DS, but with some added features like taking your own pictures and using the pattern as custom camo. They also showcased 2 Dance Dance Revolutions games for the wii and while I haven't played a DDR game in years, I might check it out. A couple games that caught my attention were a spinoff of Gradius called Otomedius (replace ships with cute anime girls) and another called Already Dead. Both of which look like something I'd like to check out.

Warner Brothers Interactive - I didn't see much of them, but I did get a chance to preview Arkham City. I have yet to play the original, but this one had me sold with both the mechanics and the environments. The downside is that its not multiplayer, as was speculated in the past. Regardless, its definitely something to check out.

Namco-Bandai - I unfortunately, got to check them out a bit too late, but I was at least able to play their demo of Ace Combat: Assault Horizon. The overall controls seemed a bit loose, however the game is a lot more fast-paced than its predecessors.

...on another note, a few of the people I talked to seemed impressed with some of the questions I asked them. Perhaps I should look into Gaming Journalism?