9. Paul McCartney - 'Wonderful Christmastime'
Nobody is going to argue that "Wonderful Christmastime" represents Paul McCartney's finest work. But the song's incredible popularity shows that Macca must have been doing something right back in 1979. McCartney wrote the song, and played every single instrument. According to a 2010 article in Forbes the song has been an incredible financial windfall for McCartney, earning him an estimated $400,000 to $600,000 a year: "That’s a bit less than what McCartney earns in an entire year these days from royalties on songs recorded by himself and with Wings and The Beatles. McCartney was likely motivated to record the holiday standard in part because of his disastrous financial experience with The Beatles."