The music changes periodically based on what's popular at the time. Our first cruise in 02 we heard "who let the dogs out" several times around the family pool, but in Jan 03, didn't hear it (made me happy, cause I was sick of it, DD really liked that CD).
I did notice the single shuffleboard court on the Wonder, because we actually had to wait to use it, and I went over to the other side searching. I thought I was nuts cause I knew there were two of them on the Magic!
Anyway, in the hallways, I often heard the "softer" songs in the late evening early morning hours, and the more upbeat songs during the day. I specifically remember hearing "Candle on the Water" from Pete's Dragon, because I hadn't heard it in years!