I've had a couple of wireless presenters (the little devices with a USB receiver which allow you to move PowerPoint presentations etc along remotely) and I've found that they're great when they're close to the laptop, but rubbish at any significant range.
This isn't a problem when presenting tech talks, but when preaching it's much more of an issue - churches tend to be longer than the 15m of advertised range for most presenters.
There are a few wireless presenters which claim a 30m range, for example the Speedlink SL-6199. Does anyone have any experience of devices which really work at this distance? I'm slightly skeptical.