An increasing number of researchers use audio-visual facilities to present their papers (from the traditional overhead projector to the more spectacular Powerpoint slide show), which means that you have to take this aspect into account when you select the venue for your conference. Ask your speakers well in advance which facilities they might require. This might range from video and sound facilities to computer and network connections. Checking that these facilities are available at the venue of your choice, is not enough: you will also have to enquire whether the institution hosting your conference is able to put some technical assistance at your disposal - microphones and computers have a well-known disposition to stop working when you need them most. If at all possible, familiarize yourself with the audio visual equipment (and do it before the day of the conference!).