In my opinion, the top places are
Inn at Robert's Grove -- lovely small resort, with A/C, pool, tennis, good restaurant
Rum Point Inn -- one of the original resorts north of the village, with free-form cabanas and new A/C apartments, new pool, nice beach
Kitty's -- classic barefoot place, one of the best beaches, good restaurant and bar, beachfront cabanas don't have a/c but are wonderful anyway
There are many other good places in all price categories. Nautical Inn, Serenity, Green Parrot Cottages among others are good spots north of Placencia village. In the village are mostly budget/moderate places. Some of the best are Tradewinds, Harry's Cozy Cabanas, Ranguana and Seaspray.
There are also some rental cottages. Kitty's rents some, and Barnacle Bill's up at Maya Beach are new and nice.
Belize First Magazine http://www.turq.com/belizefirst/