1.
Meeting Devs, and having them passionately tell me about their game, and why it's cool. No "Awesome button" stuff, I don't need Marketing PR. Tell me what makes your game different from the guy in the next booth who's going to be using the same buzzwords you might (Immersive, Evolutionary, Revolutionary). I stop listening right there, because I know you're just trying to PR me into believing. Let me talk to Casey Hudson, 'cause I'm pretty sure that guy is going to passionately tell me about something, and I'll listen to him. People who are passionate about a game, put 110% into it, and they make great games. People who hand me marketing buzzwords are just trying to sell Yet Another Shooter, trying to ride a bandwagon.
Super-cool swag doesn't hurt either. Not because I'm easily entertained, but because it tells me alot about the team and the company. If you're giving away something cool, it tells me...
-You believe in the game enough to spend some money promoting it because you're certain it's going to sell. Which returns us to the part about passion.
-Your team is creative enough to come up with something cool. Which means they were creative enough to come up with a cool game.
2.
You want to really impress me? Setup a webcam with a chat feed, and rotate Devs through to answer questions and talk about the game. With average joes. Give us the same treatment you would if we came to your booth. I can get enough PR videos from other games. Go back to your roots, I remember when Black Isle and Bioware would discuss all kinds of things on message boards, that's what made those studios great, that we could discuss things. Do it again, Leave the carefully contrivied videos to the other studios, show me you're different, show me you're passionate, and talk with me about your game!
The giveaway isn't a bad idea either. A "Bag-O-Swag" for people who may never go would be a huge idea. Kind of like what Computer Gaming World used to do, they'd give out a few packages of swag they'd picked up on the floor.
You could do a Bioware centric version. Whatever you're handing out, maybe a thumb-drive with your promotional material. Maybe a signed print/sketch or two from the artists. Signed photo of the team. Maybe even a poster you used after the show. Honestly, you could probably do the whole thing dirt cheap and I think you'd be amazed at the response.
Oh, and a picture of Tali. We love Tali!
In closing, I reiterate, Show your passion!. Everyone's going to be out there with videos, demos, Marketing guys dropping as many buzzwords per sentence as they can possibly fit. Want to stand out? Have the Team tell me about your game, why it's great, and talk with me about it.