We will occasionally book on a lower deck, especially on Carnival where the standard oceanview cabins are large enough to accommodate three adults comfortably.
As with the selection of any cabin, I make sure to study the deck plan of the deck I'm considering as well as the decks immediately above and below. My preference is to be between two decks of cabins, but that's not always possible. We usually end up over (or under) a library, information lobby, or something else that is usually quiet. Avoid being near/over/under show lounges and the casino, if you can. Also, if there's something on the deck plan that's not identified, I'd avoid that, too. (It could be a crew bar, for example.) I also avoid the lowest passenger deck for that reason -- you don't know what will be directly below you.
Let us know what you decide, or have decided.