Here's an additional note on choosing space: today the organizer called us in to choose our space for next year's show. Our time to meet the sales person was set on our seniority in the show (a combination of how many years we had consecutively exhibited at the show, sizes we had purchased, position on the board, how much advertising space we had purchased in the association magazines). At the meeting, we were shown a floor plan with the spaces that already been sold in front of us marked out. We reviewed the plan and chose a space that maximized our place on the floor, took into consideration where we were in relation to competitors and partners and the size we could afford. We'll get an invoice and pay 50% within 90 days.
This is a civilized way of choosing space. Some organizers put all of the exhibitors in the same room at the same time and call you in order, ala the NBA Draft. You wait your turn and watch as the prime spaces are picked off by the highest seniority exhibitors.
I have no preference as to how to choose, but you need to be prepared with your choices in order and with your plan of where you want to be.