I thought maybe this could be a separate thread, as content is added every week. Here's the big list so far:
Downloadable Tracks (in order of release)
Metallica "Ride the Lightning"
Metallica "Blackened"
Metallica "And Justice for All"
Police "Can't Stand Losing You"
Police "Synchronicity II"
Police "Roxanne"
Queens of the Stone Age "3's and 7's"
Queens of the Stone Age "Little Sister"
Queens of the Stone Age "Sick Sick Sick"
Creedence Clearwater "Fortunate Son"*
Foreigner "Juke Box Hero"*
T-Rex "Bang a Gong (Get It On)"*
The Knack "My Sharona"*
The Runaways "Cherry Bomb"*
Wolfmother "Joker & The Thief"
David Bowie "Moonage Daydream"
David Bowie "Heroes"*
David Bowie "Queen Bitch"*
Black Sabbath "N.I.B."*
Black Sabbath "Sweet Leaf"*
Black Sabbath "War Pigs"*
Ramones "Rockaway Beach"
The Clash "I Fought the Law"
Buzzcocks "Ever Fallen in Love"*
Radiohead "My Iron Lung"
Weezer "Buddy Holly"
The Pretenders "Brass in Pocket"*
30 Seconds to Mars "Attack"
30 Seconds to Mars "The Kill"
All-American Rejects "Dirty Little Secret"
All-American Rejects "Move Along"
The Sounds "Song with a Mission"
Lynyrd Skynyrd "Gimme Three Steps"
Black Crowes "Hard to Handle"*
Rush "Limelight"*
The Hives "Die All Right"
Iron Maiden "Number of the Beast"*
Stone Temple Pilots "Interstate Love Song"
Sweet "Action"*
The Monkees "Last Train to Clarksville"*
Blink 182 "All the Small Things"
Oasis "Don't Look Back in Anger"
Oasis "Live Forever"
Oasis "Wonderwall"
Smashing Pumpkins "Siva"
Rush "Working Man"*
Coheed and Cambria "Ten Speed (Of God's Blood and Burial)"
B-52's "Roam"
Faith No More "We Care a Lot"
Kiss "Calling Dr. Love"
The Clash "Complete Control"
The Police "Truth Hits Everybody"
The Ramones "Teenage Lobotomy"
Stone Temple Pilots "Sex Type Thing"
Weezer "El Scorcho"
Garbage "Why Do You Love Me"
Nine Inch Nails "March of the Pigs"
Nine Inch Nails "The Collector"
Nine Inch Nails "The Perfect Drug"
Grateful Dead "China Cat Sunflower"
Grateful Dead "Casey Jones"
Grateful Dead "Sugar Magnolia"
Grateful Dead "Truckin"
Grateful Dead "Franklin's Tower"
Grateful Dead "I Need A Miracle"
Black Tide "Shockwave"
Paramore "Crushcrushcrush"
Serj Tankian "Beethoven's C***"
At the Gates "Blinded By Fear"
Evile "Thrasher"
The Haunted "D.O.A."
Songs marked with an asterisk are covers.
Downloadable Tracks (in order of release)
Metallica "Ride the Lightning"
Metallica "Blackened"
Metallica "And Justice for All"
Police "Can't Stand Losing You"
Police "Synchronicity II"
Police "Roxanne"
Queens of the Stone Age "3's and 7's"
Queens of the Stone Age "Little Sister"
Queens of the Stone Age "Sick Sick Sick"
Creedence Clearwater "Fortunate Son"*
Foreigner "Juke Box Hero"*
T-Rex "Bang a Gong (Get It On)"*
The Knack "My Sharona"*
The Runaways "Cherry Bomb"*
Wolfmother "Joker & The Thief"
David Bowie "Moonage Daydream"
David Bowie "Heroes"*
David Bowie "Queen Bitch"*
Black Sabbath "N.I.B."*
Black Sabbath "Sweet Leaf"*
Black Sabbath "War Pigs"*
Ramones "Rockaway Beach"
The Clash "I Fought the Law"
Buzzcocks "Ever Fallen in Love"*
Radiohead "My Iron Lung"
Weezer "Buddy Holly"
The Pretenders "Brass in Pocket"*
30 Seconds to Mars "Attack"
30 Seconds to Mars "The Kill"
All-American Rejects "Dirty Little Secret"
All-American Rejects "Move Along"
The Sounds "Song with a Mission"
Lynyrd Skynyrd "Gimme Three Steps"
Black Crowes "Hard to Handle"*
Rush "Limelight"*
The Hives "Die All Right"
Iron Maiden "Number of the Beast"*
Stone Temple Pilots "Interstate Love Song"
Sweet "Action"*
The Monkees "Last Train to Clarksville"*
Blink 182 "All the Small Things"
Oasis "Don't Look Back in Anger"
Oasis "Live Forever"
Oasis "Wonderwall"
Smashing Pumpkins "Siva"
Rush "Working Man"*
Coheed and Cambria "Ten Speed (Of God's Blood and Burial)"
B-52's "Roam"
Faith No More "We Care a Lot"
Kiss "Calling Dr. Love"
The Clash "Complete Control"
The Police "Truth Hits Everybody"
The Ramones "Teenage Lobotomy"
Stone Temple Pilots "Sex Type Thing"
Weezer "El Scorcho"
Garbage "Why Do You Love Me"
Nine Inch Nails "March of the Pigs"
Nine Inch Nails "The Collector"
Nine Inch Nails "The Perfect Drug"
Grateful Dead "China Cat Sunflower"
Grateful Dead "Casey Jones"
Grateful Dead "Sugar Magnolia"
Grateful Dead "Truckin"
Grateful Dead "Franklin's Tower"
Grateful Dead "I Need A Miracle"
Black Tide "Shockwave"
Paramore "Crushcrushcrush"
Serj Tankian "Beethoven's C***"
At the Gates "Blinded By Fear"
Evile "Thrasher"
The Haunted "D.O.A."
Songs marked with an asterisk are covers.