The Fictional Groups You would Join...

[Helimocopter]

Ultramarines, The Holy Emperor of Mankind's finest soldiers.

 

[revenge6000]

http://www.fallenearth.com/node/49

 

[Akai Shizuku]

http://www.uesp.net/w/images/images.new/3/3c/HouseRedoran_flag.png

That or Morrowind's Werewolves. Or a vampire clan; they actually have good vampires.

 

[CounterAttack]

Jedi. Need I say more?
Alternatively, if they put me in control of a Tau battlesuit...

 

[Jaxek13]

Organization XIII, Brotherhood of Steel, The Alliance, The Jedi Order, The Assassins, and The resistance in Jak II.

 

[DanDeFool]

The Boondock Saints, because sometimes the legal system just doesn't work.

 

[Lt. Vinciti]

Brotherhood of Steel

Knights of the Nine

House Redoran

Skaal

 

[WolfThomas]

If they'd accept me as I am now, The Blades (Oblivion), the Brotherhood of Steel (Fallout), Spectre (Mass effect), the Gray Wardens (Dragon Age) and the Nova Corps (Marvel Universe).

Of course if the Avengers if I had powers/magic/technology that allowed me to be considered an equal. The Anarchs (VTMB) also if they turned me.

 

[T3h Merc]

I'd join a load but as a completely useless, wisecracking, red shirt who never shows his face and is always being reincarnated.

The Normandy Crew. (Space Helmet. All the time.)
The Serenity Crew. (Dark Brown Duster)
The Brotherhood of Steel. (Full Armor)
The Dark Brotherhood. (Dark Colored Robes)
Task Force 141 (Cover my mouth with a dust rag, and eyes with goggles.
The Team Fortress 2 team. (Medic FTW)
The International Contract Agency. (Wear a Suit and gloves.)
The United Nations Space Command. (Hide my face with a sheet of Bullet resistant tinted glass.)
The Orbital Drop Shock Troopers. (Again full combat armor)
The Coalition of Ordered Goverments (But I'd wear the helmet)

EDIT: 385th post (It's my favorite number.

 

[Naheal]

Spoiler: The Black Knights

 

[Syntax Man]

The Order of the Black Nights-Code Geass
ODST
ZAFT
State Alchemists

 

[TacticalShoe]

The crew of Serenity, totally.

 

[Estocavio]

The Cult Of Blessed Agonies. - 6 Days A Sacrifice.

 

[malestrithe]

AVALANCHE.
The Brotherhood Outcasts
Whatever clan Ryu Hayabusa is affiliated with
Shadaloo.

 

[traceur_]

The Zanarkand Abes.

Because Blitzball is the most awesome fucking thing ever.

Alternatively: The Runners from Mirrors Edge.

 

[Phyroxis]

Dark brotherhood.

 

[Grayjack]

SEES from Persona 3, Squad 7 from Valkyria Chronicles, and the Embryon from Digital Devil Saga.

 

[sup3ri0r]

Yeap, The Dark side or one of the bounty hunters XD

 

[WaywardHaymaker]

Indeed.

Spoiler

Or maybe Task Force 141, but I doubt I'd be that good. And I'd probably be dead now because I'm not named Soap or Price.

 

[Seasons of Bailey]

I'd join a load but as a completely useless, wisecracking, red shirt who never shows his face and is always being reincarnated.

The Normandy Crew. (Space Helmet. All the time.)
The Serenity Crew. (Dark Brown Duster)
The Brotherhood of Steel. (Full Armor)
The Dark Brotherhood. (Dark Colored Robes)
Task Force 141 (Cover my mouth with a dust rag, and eyes with goggles.
The Team Fortress 2 team. (Medic FTW)
The International Contract Agency. (Wear a Suit and gloves.)
The United Nations Space Command. (Hide my face with a sheet of Bullet resistant tinted glass.)
The Orbital Drop Shock Troopers. (Again full combat armor)
The Coalition of Ordered Goverments (But I'd wear the helmet)

Strange how wearing a helmet increases your chances of dying, is it not?