Which ship?
On the Dream and Fantasy, we prefer Deck 8, mid ship, starboard side. There are a couple of reasons:
1. It seems like less movement mid ship (we were all the way in the back once and it was vibration city)
2. Deck 8 is pretty central. We try to use only the stairs on the ships (then we don't feel as guilty eating desserts), so Deck 8 is only 3 decks from the pool and Cabanas, and its 5 or 6 down to AP, EC, and RP.
3. I like having staterooms above and below me. I was on a different cruise line once, on a high deck, right below the pool, and had to deal with scraping pool chairs every morning around 5am. NOT my idea of a good vacation! lol
4. Starboard side is the side facing
Castaway Cay when you dock there.
On the Magic, we prefer Deck 7, mid ship, starboard side, for the same reasons.
Good luck choosing!