Grats! It’s an exciting time for sure! You never used VR before? You are in for a treat!
It’s kind of like Wii in some games I guess, in terms of strenuous movement. You won’t want to get Thrill of the Fight yet, for example - which is awesome but pretty close to the movements you would do when actually boxing.
Start with the built-in demos, like First Steps. If you are showing it off to kids, they will especially love the Bogo demo.
Beat Saber has a demo too. It is the number one recommended VR game for a reason (near universal appeal) but you can try it first before buying.
Then along with what others have said, my top premiere native Quest experience recommend would be In Death Unchained. It’s a rogue-lite archery game with a Souls-ish atmosphere, really nice and satisfying when you start pulling off the good shots.
For apps, DeoVR is the best VR video player, it’s free and has a native Quest version.
I like Wander, which is basically a Google Street View viewer in VR. It’s not 3D but lets you sit inside 360 panorama images of views from anywhere in the world, and is kind of cool to wander around or go to random places. On the PC side you do have Google Earth VR (free), which is highly recommended to check out also. Get the Oculus Store version. It includes the street views too, but is done in a different way to Wander, which is kind of built around that one thing.
Eventually you will want Virtual Desktop to try wireless PC streaming, if you have the good Wifis. I don’t think you need it Day 1.
You’ll also want to stuff about with SideQuest, to do that you need to set yourself up with an Oculus developer account to make it work so again probably not Day 1.
Using Link you will be able to play Rift games too, if your PC is up to it. I’d say Lone Echo is still the number one made-for-VR game that really shows off the medium. Asgard’s Wrath and Stormlands are also popular bigger-budget choices.
And of course Steam VR games - you are keen on seated PC games, and have named a bunch of those earlier. Obviously you will be getting Skyrim VR - really cool to see the familiar world from a different perspective, but VR is tacked on so the UI is somewhat clunky. In the same vein, Fallout 4 is also cool but it never ran that well for me.
You already have No Man’s Sky which includes VR, so that’s a no brainer. Awesome but brutally hard on the system specs, so don’t expect a smooth experience. Elite Dangerous is much smoother and superb too.
For racing games I’d recommend Project Cars 3. Great VR support, and more of a game than a sim. Even better with a wheel.
And then we have the flight sims. DCS World and IL-2 Sturmovik Great Battles are both fantastic. DCS has better VR support, in that you can play the whole game without touching a mouse once you’re set up, but IL-2 is a bit simpler to get into. HOTAS recommended.
And of course the number one PC VR game which I would assume you will be getting, is Half-Life Alyx. Unless you just hate Half-Life… ;)
Special mention to Minecraft for Windows 10, which got a free VR update. I think the worlds this generates are just amazing in VR, such a grand sense of scale.