Action. The world revolves around it. People thrive on it. Everybody wants a piece of the action, 'cos it's fast, it's furious, and if it's in man form in all likelihood it will have an eagle eye and moulded plastic underpants. Who could ask for more?
Broadly, there are two different types of 3D action games: Quake-style games, otherwise known as first-person shooters, and, for want of a more descriptive categorisation, others.
Both involve fast-paced, reaction-based gameplay, usually very little thought, and in the case of the first-person shooters a multiplayer variant of the game played online or over a LAN known as deathmatch, which encourages you to redecorate virtual walls with the contents of your fellow players' polygonal bodies.

Heading up the list of great first-person shooters is Quake III Arena from id Software, the guys who started the whole thing off many years ago with a game called Wolfenstein 3D. Maybe they're more like 'ego Software' these days, but the game is still of high pedigree, and caters well to deathmatch novices.
Unreal Tournament from Epic Megagames has risen to usurp, in the eyes of many veteran gamers, the classic game of Quake, providing faster, harder gameplay and more options than just straightforward deathmatch.
As far as the 'others' go, example classics include the likes of Eidos' Tomb Raider series which combines action and adventure with an intricate 3D platform game (and comedy breasts), and Activision's Mechwarrior games, in which you control a lumbering 200 ton robotic behemoth of destruction in a series of pitched and intense battles.
Dodgy apples in the 3D action bobbing barrel include the well and truly bruised Nocturne from Take 2 (how not to do a horror version of Tomb Raider) and Microsoft's rotten Trespasser (marred by a horrid interface and dull gameplay). Let's not forget the literally festering, maggot-ridden Turok 2 (a truly awful console conversion) from Acclaim (or not as the case may be). Bite at your own risk.
Now read our 3D Action Game reviews