Harley is a tough guy, while the rhyming Marley has a softer, gentler image. The name brings to mind reggae great Bob Marley, as well as the lovable dog from bestseller Marley and Me.

Reggae master Bob's surname was one of the biggest risers on the popularity charts for girls in 2008, with spellings Marlee and Marely also leaping in favor. Also used for boys, Marley is one of the top unisex names in the US.

The combined inspiration of reggae master Bob and the dog-loving romp "Marley and Me" catapulted this name up the chart in recent years. But what goes up....