(adsbygoogle = window.adsbygoogle || []).push({}); WIP = Work in progress. Please submit what you have unlocked and how, and I'll be sure to add it in
Will also add pics when I have time... until then here is the start of the list.

Titles
FNG - Welcome to Modern Warfare 3
S.S.D.D. - Unlocked at Private I (Lv2)
Sgt. - Unlocked at Sergeant First Class (Lv20)
1st Sgt. - Unlocked at First Sergeant (Lv28 )
Far Superior - Unlock in the Prestige Shop
Sidekick - Get 3 kills in one life with your secondary weapon
The Mad Bomber - Plant 2 bombs
The Avenger - Avenge a fallen teammate
Laying the Bomb - Kill a bomb carrier in Sabotage or Search and Destroy
The Legend - Be the last man standing in Search and Destroy
Drifter - Destroy a car
Accident Prone - Fall 15 feet or more and survive
No. - Kill an enemy cooking a Frag Grenade
Bow Down - Kill 15 enemies while you are crouching
Joint Ops - Get 15 assists
Slight of Hand Pro - Get 300 kills using Sleight of Hand
FMG9 - Achieve maximum weapon proficiency with this weapon
Flags - I think they're unlocked at lvl 3 or 4?

Living Dead- Survive a final stand