Every console has must have games, but only a handful of them are worth buying the system for, and only one defines the machine. Since most consoles live more than five years, pinpointing that one game requires key analysis, lots of arguing and a few punches. It was tough, but we managed to come up with a list of these gems. Naturally, we expect you to tell us whether we got them right.

PlayStation 3- Uncharted 2: Among Thieves

It took almost three years, but PlayStation 3 finally has its must have with Uncharted 2: Among Thieves. Several quality games preceded it, including Killzone 2, Ratchet & Clank Future: Tools of Destruction and the original Uncharted: Drake's Fortune, but Among Thieves is the machine's showpiece, thanks to Hollywood caliber cut scenes, incredible acting, intense gunplay and a story full of plot twists. It's one of the few games that not only justifies spending $299 for the system, but also blurs the line between action flick and video game. Time to jump on the PS3 bandwagon.

Wii- Wii Sports

Barring some mind-blowing idea from Nintendo, it appears that Wii Sports will always be the system's most important game. After years of entertaining its fans with Marios, Zeldas and Metroids, Nintendo branched out and attracted new customers with a motion sensitive controller and the ultimate game to go with it, bundled software that lets them experience virtual tennis, bowling, baseball, boxing and golf like never before. Before long, moms, grandmas and uncles were off the couch and hitting homeruns. Unless sales plummet, Wii Sports may become the single most important video game in history.

Nintendo DS- Nintendogs

With Nintendogs, Nintendo ushered in a new generation of virtual pets, ones that allowed for a deeper level of interaction. That was all thanks to the DS hardware and its microphone/touch screen. Users not only scratched their canine companions, but called them by name. This excellent demonstration of the DS' abilities helped to solidify its place as the current number one handheld.

Xbox 360- Halo 3

Microsoft's Xbox 360 had an impressive launch, thanks to games like Call of Duty 2, Project Gotham Racing 3 and Condemned: Criminal Origins, but despite the attractive lineup, everyone was hungry for more Halo.

Well, Bungie delivered the quality experience they craved with Halo 3. Although we can debate the single-player campaign's impact, multiplayer was and still is huge. Bungie took everything we loved from Halo 2 and improved it, with additional maps, weapons, vehicles and match making capabilities; it's still one of Xbox Live's most played games. On top of that, fragging enemies looks sweeter in high definition.

PC (yes, we know it's not a console)- World of Warcraft

Sony Online Entertainment kicked off the MMO craze with EverQuest, but that series pales in comparison to World of Warcraft. Blizzard not only shoved the genre into the spotlight, but also the PC, giving it a much cooler edge. Suddenly, WoW had five million subscribers, then six, then ten. It appeared on South Park and then bottles of Mountain Dew Game Fuel. Sure, PC has a legacy of hit video games (Half-Life 2, Doom, Grim Fandango), but none of them touch WoW's mainstream success.