Here is the full list of all 50 Battlefield: Bad Company achievements worth 1,000 gamerscore.
Completed one mission without dying (any difficulty)
Completed 'Welcome To Bad Company' on normal
Completed 'Ghost Town' on hard
Hit hostile helicopter with laser designator
Found all gold bars
Found all collectables
Completed 'Crash and Grab' on hard
Climbed to the highest spot in the game
Completed 'Air Force One' on hard
Completed 'Acta Non Verba' on hard
Completed 'Crossing Over' on hard
Killed 25 enemies
Destroyed 200 Walls
Killed 25 enemies in a helicopter
Drove all vehicle types (Jeep, Tank, Heli, Boat)
Completed 'Par for the Course' on hard
Found half of the gold bars
Knocked down a small forest
Destroyed 50 vehicles. (containing enemy AI)
Found half of all collectables
Destroyed 1000 walls
Collected 5 unique dog tags
Reached Rank 8
Found 5 unique collectables
Placed #1 in a Ranked Match
Found one gold bar
Completed 'Welcome To Bad Company' on hard
Used auto Injector 50 Times
Reached Rank 3
Used Squad in the menu, found a friend and played one round
Played one complete ranked online match
Took 3 pictures using the image system
Complete 'Acta Non Verba' on normal
Complete 'Crossing Over' on normal
Complete 'Par for the Course' on normal
Complete 'Air Force One' on normal
Complete 'Crash and Grab' on normal
Complete 'Ghost Town' on normal
(Online) Play 100 online matches
(Online) Knock down 1000 trees
(Online) Have 20 Squad members spawn on you without dying in a single round
(Online) Collect 50 unique dog tags
(Online) Get at least one kill in every vehicle
(Online) Reach Rank 20
(Online) Reach Rank 25
(Online) 100 kills using vehicle
(Online) Glide in the parachute for 3 seconds
(Online) Achieve all the awards
(Online) Achieve half of all awards
(Online) Get 10002 kills