Killstreak rewards!
3 Kills - UAV
4 Kills - Care Package
4 Kills - Counter UAV
5 Kills - Sentry Gun
5 Kills - Predator Missile
6 Kills - Precision Airstrike
7 Kills - Strike
7 Kills - Attack Heli
8 Kills - Emergency Airdrop
9 Kills - Pave Low
9 Kills - Stealth Bomber
11 Kills - Chopper Gunner
11 Kills - AC-130
15 Kills - EMP
25 Kills - Tactical Nuke
Multiplayer Perks
Tier 1:
Marathon
Standard: Unlimited Sprint
Pro: + Get over obstacles faster
Sleight of Hand

Standard: Faster reload
Pro: + Aim down sights faster
Scavenger

Standard: Full resupply from dead bodies
Pro: + Extra magazines
Bling

Standard: Dual attachments on primary weapon
Pro: + Dual attachments on secondary weapon
One Man Army

Standard: Swap classes at any time
Pro: + Swap classes faster
Tier 2
Stopping Power

Standard: Increased bullet damage
Pro: + Increased bullet damage to cars and Killstreak vehicles
Lightweight

Standard: Move faster
Hardline

Standard: Killstreaks rewards require 1 less kill
Pro: + Deathstreaks require 1 less death
Cold Blooded (UAV Jammer on disguise)

Standard: Undetectable by UAV, air support, sentries, and thermal
Danger Close

Standard: Increases explosive weapons damage
Tier 3
Commando

Standard: Increased melee distance
Pro: + No falling damage
Steady Aim

Standard: Increased hip-fire accuracy
Pro: Hold your breath for longer when sniping
Scrambler

Standard: Scrambles the radar of nearby enemies
Ninja

Standard: Invisible to heartbeat sensors
Pro: + Move silently
SitRep

Standard: Insertions. Reveals enemy explosives and Tactical Insertions
Last Stand

Standard: Survive (on the ground) for 10 seconds after being killed, pistol equip
Pro: + Use grenades and equipment as-well as your pistol
Sources:
http://www.mw2blog.com/modern-warfar...iplayer-perks/
http://kotaku.com/5394738/modern-war...wards-revealed