Not sure if this info is 100% legit but...
Assault Killstreaks
4 Kills - Care Package
5 Kills - IMS - 3 or 4 placeable landmines that cannot be stunned or flashed
5 Kills - Predator Missile
5 Kills - Sentry Gun
6 Kills - Precision Airstrike
7 Kills - Attack Helicopter
7 Kills - Little Bird Flock - Mini Helicopters which patrol the map
9 Kills - Little Bird Guard - Big Helicopter that follows you from above and protects you
9 Kills - Mortar team - Mortar team but with 5 predator missiles - all go off at the same time in different places
10 Kills - Talcon - Mini Tank Robot
12 Kills - AC130
12 Kills - Pavelow
15 Kills - Juggernaught Suit - From spec Ops ( for anyone who sais in the spec ops video he gets it at 14 kills, well thats because he has hardline on)
Support Killstreaks
4 Kills - UAV
5 Kills - Counter UAV
5 Kills - Ballistic Duffel - Drop Juggernaught perk for the whole team, not jugg suit
5 Kills - Airdrop Trap - Drops a hacked care package
8 Kills - Sam Turret
10 Kills - Remote UAV - Target enemies with missiles
12 Kills - Advanced UAV - Blackbird
12 Kills - Remote Turret - Sentry Gun that you can control
12 Kills - Stealth Bomber
18 Kills - EMP
18 Kills - Juggernaught Recon Armour - Care Package Drop Armour
18 Kills - Escort Airdrop - Drops 5 care packages, one will be hacked
Specialist:
2 Kills - You get 1 extra perk
4 Kills - Get another perk
6 Kills - Get another perk
Yes, you do get to choose the perk you get each time.
Perks
Tier 1
Extreme Conditioning - Sprint longer distances + Climb obstacles faster
Sleight Of Hand - Reload faster + Faster weapon swapping
Scavanger - Reload ammo from bags + Spawn with more ammo
Blind Eye - Undetectable from air support + Faster launcher lock on and extra damage to air support
Recon - Explosive damage marks target on HUD + Bullet damage marks target on HUD
Tier 2
Hardline - One less kill for Killstreak + Two assists count as a kill towards next killstreak
Assassin - Immune to UAV, Motion Sensor, Thermal and Heartbeat Sensor + Immune to CUAV & EMP
Overkill - Two primary weapons + Second primary can have 2 attachments
Quckdraw - Faster aim down sights + Faster animation of using equipment and throwing grenade
Blastshield - Flack Jacket (Immune to most explosives) + Immune to stuns and flashes
Tier 3
Sitrep - Enemy equipment is visible + Enemy footsteps are more clear
Dead Silence - Your footsteps are silent + No fall damage
Stalker - Faster movement with ADS + Delay on claymores
Marksman - ID target from range + Longer hold breath on scoped weapons
Steady Aim - Increased hip fire accuracy + Faster aim down sight while sprinting
MP Map Names:
Alpha
Alps
Bootleg
Bravo
Brooklyn
Carbon
Coast
Dome
Exchange
Hardhat
Interchange
Lambeth
Meteora
Mogadishu
Paris
Plaza 2
Radar
Seatown
Underground
Village