With Christian contemporary music as our background music everyday, my kids have learn to appreciate music and therefore they also have their own favorites. I noticed that my daughter's favorites are mostly from female singers while my son's favorites are more on the 'rock' side. My daughter loves Brit Nicole's songs while my son likes the Newsboys.
As for me, my favorite songs change from time to time, depending on my mood. But mostly I like songs that somehow tells a story like Tenth Avenue North's 'Slip on By'.