Depends what you're after. The Oculus Rift S is a decent headset. Built in cameras so no faffing with external cameras or laser emitters.

The Valve Index is considered one of the top ones, and the controllers are awesome with finger tracking, force sensors, and they strap to your hands so you can let to of them without dropping them.

There are also plenty of cheaper Windows Mixed Reality headsets. Possibly not the best tracking, built in cameras and varying quality.

How does that effect the gameplay?

Generally I think they work pretty well. They may not have the best resolution and FOV though, and camera based trackers can get a bit janky when reaching behind your back and the controllers go out of view of the cameras. But as something to get into VR they can be pretty decent.

One thing I also love about the Index is the headphones/speakers. They don't touch your ears so they never get uncomfortable and the sound from them is amazing (maybe lacking a tiny bit of bass though).

I've done a bit of searching and reading since my dumb question. I suppose the thing is I was bitten by the VR bug years ago when I tried a headset (no idea what it was) in our local indy game store, now defunct. And it was resurrected, don't laugh, when I mucked about with the stocking-filler Cardboard VR things I got my kids for Christmas, a couple of years back.

My issue is that my head says I'd probably be fine with something cheap for the occasional taste of VR for fun, whereas another part of my head says I shouldn't be daft, I should get something that actually works properly with real VR games. That's all very well, but the latter category can get eye-wateringly expensive very fast, particularly if I need a major upgrade on my PC.

I shall just have to ponder a bit, I think.

It'll be interesting to see if prices fall back down to earth anytime soon.

Some prices aren't too bad as these things go. In particular some of the Windows Mixed Reality kit is relatively cheap and there's a fair bit of it around on the used market for even less. On the other hand, if you've got the cash you could easily spend £2-3,000 for a high end setup including a new graphics card. 
 

I'd go entry level, either a new Rift or a second-hand Vive. I went for the latter, on the assumption that room-scale just wouldn't suit some buyers' lifestyles, and so it proved. I picked up a complete, virtually new Vive rig for £450, and I suspect you could get one for less now. But I live alone and if I want to push all the furniture to the wall, I can.

I've supplemented it since with a new audiostrap (a worthwhile investment) and two additional second-hand controllers for days I'm really bingeing - or for workshops. That's another thing - I've recouped the cost by running a few workshops (as easy as instructing people how to do some basic 3d drawing in Tiltbrush) and a brief residency with Opera North, supporting a performer who wanted live improvised drawing in the background as he sang.

Rifts are neater but with lower resolution, and can be operated sitting down for many games.

For anyone who's a big fan of Half life, Alyx alone is worth the cost of a VR rig.

As Chrisss says, it's chronologically HL 1.5. I'm guessing now they've built the engine and all the assets for VR, HL3 could be implemented as another VR game, or even a DLC, with comparative ease. I think they'll want to do it too, for the sake of completion of the series. There's also talk that HL2 Chapters is going to be re-released for VR.

I'm going back in at that level to see if I can kill all the headcrab zombies by luring them into the room with the barnacles, one by one.

I'm now 9 hours into Alyx, by far my longest play sessions. I haven't used my headset a great deal recently and I have been experiencing the real life vs VR strangeness again. I was going to bed the other night and I could see the blue grid from the play space boundaries when I shut my eyes. And last night I got into bed and thought I was wearing the gravity gloves and went to take them off.

The game is stunning. The sound and visuals of the environments are amazing, and there are some proper scary moments.

My most sensorily confused moment came in (ironically) A Chair in a Room: Greenwater, when I tried to sit on a virtual chair. Very uncomfortable. Incidentally, I recommend Greenwater too, if you don't have it already; not perfect and a bit long in the tooth, but well-told, intriguing and scary as hell.

I went back to the start of Is or Will Be and retreated to the Barnacle room over and over again to kill all the headcrabs, saving my bullets just for the headcrab zombies. Just as well when I came across the Combine soldiers later in the level.

Can you do screengrabs?

I took a few by accident, but they're not very edifying. When I go back in later this afternoon, I'll take some sexier ones.

Haha, that sounds dangerous. Did you fall flat on your arse? :D VR can have some bizarre effects. I've nearly fallen over bending down and trying to stabilise myself on a nearby wall. There's a bar in Alyx and I really wanted to take a seat and pour myself a drink.

I do have A Chair in a Room but I haven't got very far. I found it a little frustrating, partly the Index controllers trying to emulate the Vive controllers. When Alyx is done I will try it again.

Have you got to chapter 7 yet? :O Oh my god that is some tense crazy shit going on! I had to take a break at one point and lots of swearing!

I haven't found the game particularly difficult. The enemies are pretty predictable (combine are mostly shoot, pause, shoot), head crabs are less jumpy and slower that they used to be, and J*** **********.

Screenshots really don't do it justice.

Hmm, I tried uploading two more but that don't seem to have worked on my phone.

Found toilet paper! Out of stock in the shops, but at least I can get it in VR :D

Lovely.

I think screenshots in VR are a little like taking a picture of the Grand Canyon - it just loses the scale that you experience when you are there.

Here's some more anyway.

Some of the game seems a bit - janatorial?

That's dystopias for you.