The two grandest suites, in my opinion, are Suites E and F on Upper Deck. They were built from a space that used to house a public room, and the original woods are still there. The cabins directly next door to each, U90 and U91, also have some elements of this once grand space. These last two are classified as mini-suites.
Suites 1 and 2 on Sun Deck are original to the ship. Their proximity to the outdoor promenade and the beautiful Commodore Lounge makes them good choices, as well.
But, as Dave said, these may have sold out by now for your particular sailing. Do you have an assigned cabin number, or category number? (You can send this info via a private message, if you prefer.) I sailed in a Category 4 on Upper Deck, and checked out many other cabins while on the ship, and can offer some tips.