Marathon (Tier 1)
Standard: Unlimited Sprint
Pro: Get over obstacles faster
Sleight of Hand (Tier 1)
Standard: Faster reload
Pro: Aim down sights faster
Scavenger (Tier 1)
Standard: Retrieve ammo from dead bodies
Bling (Tier 1)
Standard: Dual attachments on primary weapon
Pro: Dual attachments on secondary weapon
One Man Army (Tier 1)
Standard: Use primary weapon in secondary slot
Stopping Power (Tier 2)
Standard: Increased bullet damage
Pro: Increased bullet damage to vehicles
Lightweight (Tier 2)
Standard: Move faster
Hardline (Tier 2)
Standard: Killstreaks rewards require 1 less kill
Pro: Deathstreaks require 1 less death
Cold Blooded (Tier 2)
Standard: Undetectable by UAV, air support, sentries, and thermal
Danger Close (Tier 2)
Standard: Increases explosive weapons damage
Commando (Tier 3)
Standard: Increased melee distance
Increased melee speed Steady Aim (Tier 3)
Standard: Increased hip-fire accuracy
Scrambler (Tier 3)
Standard: Jams enemy radar
Ninja (Tier 3)
Standard: Invisible to heartbeat sensors
Pro: Move silently
SitRep (Tier 3)
Standard: Insertions. Reveals enemy explosives and Tactical Insertions
Last Stand (Tier 3)
Standard: Survive after being killed for 10 second, pistol equipped. You can crawl too
[via MW2blog]