Here is the full list of all 36 Tom Clancy's Rainbow Six Vegas achievements worth 1,000 gamerscore.
Kill 500 terrorists online or offline
Kill 150 terrorists using only a Pistol
Complete all maps in splitscreen T-Hunt at Realistic difficulty
Complete all maps of splitscreen Terrorist Hunt on Normal difficulty
Used the Xbox Live Vision to create a character with your appearance
Cooperatively complete all Terrorist Hunt missions
Play all maps of every Adversarial game mode
Deposit the canister and kill an enemy canister carrier in the same Retrieval match
Most kills in a ranked online Sharpshooter match
Defuse the bomb within 2 minutes in Attack & Defend
Recover the Intel in Attack & Defend within 2 minutes
Leading contributor of kills for the Defenders in a winning Attack & Defend ranked match
Rescue all hostages in an Attack & Defend mission in under 5 minutes
Most kills in a winning online ranked match of Team Sharpshooter
10 consecutive player kills without dying
Complete the single player Story Mode at Realistic difficulty
Cooperatively complete the Story Mode
Kill 50 players using Explosives only
10 kills using a Sniper rifle in an online ranked match
Be the only remaining player in a ranked online match of Survival
5 consecutive player kills without dying
100 total player kills in any adversarial mode
Achieve the rank of Private 1st Class
Most kills in a winning online ranked match of Team Survival
Complete a Cooperative T-Hunt mission with at least one other player
Complete a Cooperative Story mission with at least one other player
Completed Nevada Dam in single player Story Mode
Completed Dante’s Casino in single player Story Mode
Completed Vertigo Spire in single player Story Mode
Used all Gadgets at least once in single player Story
Completed Downtown Vegas in single player Story Mode
Completed Calypso Casino in single player Story Mode
Completed Border Town in single player Story Mode
Host a 16-player match
Achieve the rank of Elite
Achieve the rank of Lieutenant 2nd Class