One thing to consider also, is how will you be collecting your leads. Just asking people to hand over their business card is effective, however it does not yield as many leads as other methods. Holding a contest where people drop their business cards in a ballot is one of the best ways to get leads. Its inexpensive, fast, and yields a higher lead turnover then simply asking people for their information.

The Tradeshow Mentor
http://tradeshow-mentor.blogspot.com/