Sometimes, I'll say I "like" someone, but that I'm "not a fan." This just means that after I say I like someone, I want to be left alone. I like Beethoven, Lou Reed, Ella Fitzgerald, and Elliott Smith. I am not a fan, though.
I am a fan of the Spice Girls, and not much else.
But I do know that I love this song, and the way that Justin Timberlake sings it. Mmm.