Killstreaks available:

Spy Plan (3 Kills) – Shows enemies on the mini-map. Can be shot down.
RC-XD (3 Kills) – A remote-controlled explosive device.
Counter-Spy Plane (4 Kills) – Temporarily disables enemy mini-map.
SAM Turret (4 Kills) – Airdrop a placeable SAM that destroys aircraft.
Care Package (5 Kills) – Airdrop a random weapon, killstreak, or ammo crate.
Napalm Strike (5 Kills) – Airstrike that covers an area in napalm.
Sentry Gun (6 Kills) – Airdrop a placeable Sentry Gun.
Mortar Team (6 Kills) – Target three locations to bombard with mortar strikes.
Attack Helicopter (7 Kills) – Call in a support helicopter.
Valkyrie Rockets (7 Kills) – Launcher with 2 player launched, remote controlled rockets.
Blackbird (8 Kills) – Shows both enemy position and direction on the mini-map. Cannot be shot down.
Rolling Thunder (8 Kills) – Carpet bombing airstrike.
Chopper Gunner (9 Kills) – Be the gunner of an attack helicopter.
Attack Dogs (11 Kills) – A pack of attack dogs that hunt the enemy down.
Gunship (11 Kills) – Be the pilot of an attack helicopter.

( I copied and pasted that from Thumpster's guide, he allowed me.)

Now the GOOD killstreaks for kills are:

4: Care Package
9: Chopper Gunner
11: Gunship Or Attack Dogs

Good Killstreaks for Exp:

Spy Plane
Counter Spy Plane
Care Package

Good Other Killstreaks For kills
Attack Helicopter
Mortar Team
Rolling Thunder

Killstreaks you should Change in a Care Package

Spy Plane
Ammo
RC-XD
Counter Spy Plane
Sam Turret
Valkyrie Rockets

Thankyou...