Interesting that everyone has the attitude about Carnival. We went on two family friendly winter break cruises with no evidence of too much drinking, rowdiness, wild parties. We had a great time on both cruises regardless of the neon.
Yet last January we were on the Golden Princess and our neighbours next door (20 somethings) decided to host a party in their cabin and on their balcony. At 3am someone from another cabin asked them to keep it down, they apologized and immediately pumped up the volume of their CD's. I recall one particularly annoying and very grating laugh from one of their guests. We called the front desk and within minutes there was banging at their door to shut the party down. This one incident would of course not stop me from cruising Princess again.
Our next cruise is Celebrity and will be interesting to see if any difference. I am pretty sure you need to try a few lines to see which one works best for you. That's at least what we plan on doing.