It's a minor difference, but do you want to MAKE presentations on this machine or are they only meant to PRESENT them on some beamer (after making them on your desktop or downloading them or whatever)?
Any new laptop you can buy can do much more than. So that's no selection criterion worth the name.
Most beamers have a VGA-input. So your laptop should have a VGA-output. But it wouldn't harm for the future to have DVI and HDMI (that's video and sound combined) also. That excludes some.
I haven't used a laptop for many years. Now I need one for Powerpoint presentations. All other uses will be secondary.
What specifications should I go for? I don't want to go TOO minimal.