adding my 2 cents worth...we too were on deck 8 Magic in a family stateroom and definitely noticed the noise-in particular during the tropical deck party (now the pirate party) which was most inconvenient as I was trying to get a cranky 2 year old to sleep.
Since we are a family of 5, we won't fit into a "regular" room and had to have the larger room. On subsequent cruises, we've actually found it LESS expensive to book 2 smaller rooms. That was the best thing-we were able to be where we wanted to be on the ship, and we actually ended up with more space. 2 cruises ago we did joining porthole rooms. Last cruise and our upcoming 2012 cruise on kids are big enough that we did a verandah cabin for DH and I and an inside cabin across the hall for the kids.
I don't believe I would ever book a cabin underneath the pools again-personally.