I've always GM'd with my laptop, never used a screen, but I like the idea of it more and more.

I was just curious what people put on there? What do you consider essential and what has come in handy for you?

For reference I run Call of Cthulhu so especially interested in that, but I've also done DND so really just curious in general.

I was using a screen but after some time I stopped using it. Although the prints I got on the outside were cool, I felt it was kind of blocking the flow between me and players. Things that need to be hidden I open on mobile, rules lookup can be in the open, so the book is opened on the monitor on the side where it doesn't block our line of sight

Another vote for no screen! I definitely overestimated how common these were.

Now that I think of it, if I were running D&D 3.5 back when it was in full swing, and players had monster book burned into their minds, having even a shoddy copy of a page might have spoiled some fun. But I think that time has passed.

Even if the main point of a scene is a fight with tentacles GM will reveal the true nature of later, fewer players can bring up stats from seeing which page the book is open on, you might be using some homebrew from some blog anyway, or you might even be playing a more free-form system, where even meta-knowledge of the setting does not imply what the creature will do. I think many tables back then used to be more like a boardgame, where knowing what you fight against was half the battle.

And even if some OSR fan might say now "I wish those tables were back", from what I see around, nowadays there is much more flexibility, randomness and content (i.e. monsters) is not limited to a mainline that everybody knows

So even intentional peeking at GM's notes gives much less info, and unintentional does not spoil the fun

A lot of the people who responded here have focused on the secrecy, but that's actually not my goal with it really. It just seemed nice to put the laptop away for a while and have quick reference for rules and plot points all laid out at once.

Do people really have players trying to ferret out secrets that much, or that are that distrustful of dice rolls? I can't imagine anyone doing that in my group, but maybe I just have a good one.

I do focus a lot more on roleplay and discourage metagaming, so maybe that's part of it too.

viva la dirtleague dm did something I thought was neat. he had folded chits representing each party memeber and enemy (honestly did not look at how home made they may or may not have been). Then when initiatiave is rolled he lines them up and moves them over like you might do with a pool scoring thing as people take their turns and at the top of the order moves them back. I mean he was not consistant with doing that but I think that was the idea.

That is pretty cool!