Madonna's 2005 "Push" samples David Bowie's song "Fame".
Stardust's "Music Sounds Better With You" samples "Chaka Khan's "Fate".
Modjo's "Lady" song is hugely inspired by Chic's "Soup For One".
Britney's Oops song sounds like like a faster/poppier version of "Woman In Love" from Barbra Streisand.