(I've spent 88 days and 1 hour listening to Taylor 30400 times, won't go into the other artists).
Taylor Swift
Lady Gaga
Shania Twain
Rihanna
Miley Cyrus
Florence + The Machine
Natalia Kills
Beyoncé
Faith Hill
Madonna
Selena Gomez
Kacey Musgraves
Kylie Minogue
Lorde
Sam Smith
Lana Del Rey
Adam Lambert
Ellie Goulding
Cher
Evanescence
Adele
Union J
David Bowie
Hannah Montana
1000 plays isn't that difficult. 10 of these artists were basically "one era wonders" (meaning I only use 1 album by the artist, or they only have 1 album) and nearly 900 of Union J's plays came from 1 song.
Florence + the Machine - 4,951 plays
Kesha - 3,834 plays
A Fine Frenzy - 2,998 plays
Carly Rae Jepsen - 2,664 plays
Kate Nash - 2,592 plays
Imogen Heap - 2,402 plays
Katy Perry - 1,951 plays
Britney Spears - 1,931 plays
Ellie Goulding - 1,604 plays
Sara Bareilles - 1,508 plays
Marina & the Diamonds - 1,469 plays
Coldplay - 1,056 plays ()