Here is the full list of all 59 Guitar Hero III: Legends of Rock achievements worth 1,000 gamerscore.
Gold Star 20 songs on Expert
Complete Career Lefty and Righty
200k on Cult of Personality without Star Power
Use the Whammy Bar on every held note on Number of the Beast
Activate Star Power 3 times on Through the Fire and Flames on Expert
Host Ranked Online matches and win 15 consecutive songs
Join Ranked Online matches and win 15 consecutive songs
Hit 250,000 notes in Career
Earn $350,000 in career lifetime earnings
Complete Co-op Career
Complete all songs as the back-up guitar player
Complete all Co-op as the lead guitarist
Earn 100,000,000 points total in Career
Earn a 150 note streak in a Ranked Online Battle mode match
Beat any song on the expert difficulty with the games sound options turned down to zero
Complete a Career on the Easy Difficulty
Complete Career Mode on the Medium difficulty
Complete Career on the Hard difficulty
Complete all Career difficulties
Win 15 consecutive Ranked songs online using a standard controller
Play through a career on the Hard or Expert difficulty using a standard controller
Win 500 Online Ranked matches
Complete all difficulties in Career, buy everything from the shop and complete 100 online matches
Beat one of the creators of Guitar Hero 3 at their own game
Complete Career Mode on the Expert difficulty
Earn a 100 note Streak in Career or Quick Play
Earn a 250 note streak in Career or Quick Play
Earn a 500 note streak in Career or Quick Play
Earn a 1000 note streak in Career or Quick Play
Score 250,000 on a song
Score 500,000 on a song
Score 750,000 on a song
Earn 5 stars on all songs on the Easy difficulty
Earn 5 stars on all songs on the Medium difficulty
Earn 5 stars on all songs on the Hard difficulty
Earn 5 stars on all songs on the Expert difficulty
100% a song
Complete the tutorial
Buy all the Guitars from the shop
Buy all songs from the shop
Buy all characters from the shop
Refuse a boss battle
Fail a song passed 90% completion
Fail any song 10 times
Earn a 200 note streak in a Co-op match
Earn a 500 note streak in a Co-op match
Earn a 1000 note streak in a Co-op match
Earn a 2000 note streak in a Co-op match
Score 1,000,000 on any song in a Co-op match
Score 700,000 on any song in a Co-op match
Earn 5 stars on all Co-op songs for the Easy difficulty
Earn 5 stars on all Co-op songs for the Medium difficulty
Earn 5 stars on all Co-op songs on the Hard difficulty
5 Star all Co-op songs on Expert
100% a song in a Co-op match
Get an 8X multiplier in a Co-op game
Score 500,000 on any song in a Co-op match
Buy everything from the store
Complete Through the Fire and Flames on Expert