I was really deep into scene many, many years ago, and in terms of PC - 2nd Reality by Future Crew blew my mind. And still does.
A minor but important point in its favour is that it didn't require a Gravis Ultrasound, those things were annoyingly expensive.
A lot of friends who were devs got free Gravis boards by writing to Gravis directly which is why so many demos and shareware supported it.