Oh the good old times. I still remember the first time I saw what a Voodoo 1 could do. A buddy of mine bought a Diamond Monster 3D 4MB card and added it to his 2MB ATI Rage in his Pentium 200MMX. We played Need for Speed 2 SE in 640x480. In Glide mode (now long gone but was something similar to OpenGL or Direct3D back in the day) you had weather effects and nicely filtered textures. Amazing... Then Quake 2 also running smoothly in 640x480 with colored lights. And of course the original Unreal which also had native 3Dfx Glide support.
I couldn't afford such a card back then, my first own PC I bought around 1999 already had a NVidia Riva TNT2 Pro in it. But then the 3Dfx era was already past it's best. They got acquired by NVidia in late 2000 for a mere 20 million USD.
A lot more info about various 3DFx cards including rare engineering samples can be found here: http://www.thedodgegarage.com/3dfx/ (I do not own this page but in my opinion this guy has the greatest 3Dfx collection on the planet)