id Super Pack Widescreen & Multi-Monitor Guide
id Super Pack is a downloadable package containing many of id's classic FPS games. The following games are included:
Commander Keen 1-5
Wolfenstein 3D
Spear of Destiny + Return to Danger + Ultimate Challenge
Return to Castle Wolfenstein
Ultimate Doom
Doom II + Master Levels
Final Doom
Doom 3 + Resurrection of Evil
Heretic + Shadow of the Serpent Riders
Hexen + Deathkings of Dark Citadel
Hexen II
Quake + Scourge of Armagon + Dissolution of Eternity
Quake II + Ground Zero + The Reckoning
Quake III Arena + Team Arena
Most of these games are open source, and have fan-developed ports that have superior widescreen support (as well as other features) to the originals. However, Activision have only included the original versions of these games, and in the case of Quake, Quake II, and Hexen II, have not included the music. Here are tutorials for "converting" the Steam games to versions with the best widescreen support possible.
Also, if you want to launch any of these ports through Steam, follow the game-specific setup instructions first. Then open Steam, click on the "Games" menu in the top menu bar, choose "Add a non-Steam game to My Games list...". Then navigate to the executable you would normally run and select it. If it's a .bat file, make sure the file type is set to "All Files." When you select it, a shortcut to that file will appear in your My Games tab.