Vintage FPS games

[Tommy Gun]

No-ones mentioned Duke Nukem 3D!!!!!! :
Rainbow Six: Rogue Spear, a 1998 release, its actually quite addictive, and has the fun of preparing your team members to your liking with a variety of weapons and armour.
And of course, House of the Dead, which was the first modern zombie shooter.
Also, the most ballsy studio at the time, EA placed swastika's in plain sight in their first Medal Of honour, removing world war 2 taboos.
And while Far Cry 1 may not be too old, it still is entertaining.