And, have some very personable, fun people associated with your company to mingle with your guests and make an impression when you are busy with other people. Look for people who have an established reputation (not necessarily with another company, but just as "good people"); who are fun to be around, but still are perceived as professional. People who won't drink to much and get sloppy, but aren't cold fish who can't mingle and give off a holier-than-thou aura.
Roger V asked in another thread which companies were most successful marketing or branding at the show, and I am a firm believer that it's the people you send out among the attendees to mingle and chat people up who make the biggest impression...far more than any impact of signs or freebies, IMO.
I have signed up with a good dozen new sponsors since the show simply because I got to chat with the people behind the scenes, and I liked what I saw and heard, so they are foremost in my mind, more than the ones who had people who didn't bother with me.
