My first memory of BeOS was that it could play media independently. You could play a video in one window, and an MP3 or another video in another, and they'd both play audio at the same time.

I don't know exactly why, but child me thought that was so interesting, since every other OS at the time seemed unable to.

https://www.haiku-os.org/

For me it felt like it was going to be my next Amiga, in kind of experience, something that GNU/Linux never did it to me, where CLI reigns and multimedia was always looked down upon, Windows and Mac OS weren't quite there as well.

Another cool one that was around was QNX.

If I recall directly, Apple was between buying BeOS and NeXT. Would be interesting what would have happened if they went the Be route instead of the Unix route. (But given that MacOS and BeOS were both fringe at the time, perhaps they would just have gone bankrupt…)

You can pretty much just use Haiku as a daily driver these days, if your demands aren't too great. It runs really well on older hardware too.

And of course you can just spin it up in a VM if you only want to play a bit.

I just found my BeOS 5 and BeProductive CDs from the late 90s. I wish I had something to run them on.