In 2011 I started browsing the latest graphical/sound quake mods, putting together a pretty build using LordHavoc's darkplaces, rygel's ultra textures packs, the reforged packs and a variety of mods, to play quake original. Anyone can do the same, however the hassle comes when you have to browse the quakeone forums, stumbling to find the posts which detail what cvars and what configs/files you have to overwrite etc in order to get each mod to work. I literally spent as much time getting the mods working as playing the game. So I put together a nice-looking build of quake original and it's expansions called epsilon for everybody to get into, without getting into the hassle of config files and searching to find every available mod then getting them to work! The main quake build also includes the original shareware first quarter of the quake game - it is easily upgraded to the full game by dropping in the pak0.pak and pak1.pak files from the full game's id1 directory (more details below).
Version 2.1 of the Epsilon edition of the Quake expansion called "Travail".
Playthrough of Episode 1 Mission 5.
Soundtrack is from the game itself.
This is the best partial-conversion/map-pack/mod I've seen for Quake, and rivals the original game, once you get into it.
The first few levels feel like your usual space marine thing, but the further you get in... dark and interesting.
This was released by the Travail (http://quakeone.com/travail/) team in 2007, who have thankfully given their blessing for me to patch/package it for use with the epsilon builds.
It consists of 3 episodes, 15 levels, plus a secret level - plus it's own (highly atmospheric) soundtrack!
Great work by the team.