You must assemble a 7-person team to combat attacking aliens.

[Auron225]

Chuck Norris
6 recently hatched ducklings

Poor aliens...

EDIT: Or, the Cullen family from Twilight. They wouldn't win, it'd just be worth the earth to see them get taken down by aliens X)

 

[Dalek Caan]

Master Chief,
Commander Shepard,
Sovereign,
Ratchet,
Iron Man,
Garrus,
Tali.

Aliens don't stand a chance.

 

[The Salty Vulcan]

Spoiler

Sherlock Holmes

Mitchio Kaku

Chell

The Doctor

Teddy Roosevelt

Marvin the Android

Paarthurnax

Do I win?

 

[Jetut]

The Anrgy Video Game Nerd.

Samuel L Jackson.

Big Boss.

Chuggaaconroy (His puns are deadly.)

Freddiew.

Jason Voorhees.

Natsu Dragneel.

 

[C F]

Samus Aran (Expert at incorporating foreign tech)
Gordon Freeman (Primary tech expert)
FE9&10's The Black Knight (Primary defensive, unstoppable tank)
Master Chief Petty Officer Spartan-117 (Primary offensive)
Darth Revan (Secondary offensive, healing and Jedi support)

At this point, I don't need anybody else, but I'm going to add:
Dr. Brackman (Mission Control)
Commander Shepard (Diplomat)

Any alien threat will regret going toe-to-toe with this group.

 

[MammothBlade]

Major Motoko Kusanagi - Commander, Stealthy Assault Cyborg, Hacker
JC Denton - Stealthy Assault Cyborg, Hacker
Saito - Master Sniper
Uryuu Minene - Explosives Expert, Future Diary User
Laxus Dreyar - Lightning Commando
Lucy (Elfen Lied) - Psychic Commando
Joker - Ace Pilot

Their main transport would be SSV Normandy + Mako.

Master Chief,
Commander Shepard,
Sovereign,
Ratchet,
Iron Man,
Garrus,
Tali.

Aliens don't stand a chance.

Except half of your team are aliens, and at least one is pure evil

 

[XMark]

Twilight Sparkle
Rarity
Applejack
Rainbow Dash
Fluttershy
Pinkie Pie
Spike

Defeat the aliens with the power of FRIENDSHIP!

 

[Wintermoot]

The Doctor
he has experience and can probably resolve the invasion without unnecessary bloodshed.

Dr Who

please be trolling