The new Loew's on South Beach is the only new hotel on the beach in years. It's a beauty. There is a Marriott in Ft. Laudeerdale that's a beachfront rresort. Sorry I don't remember the name (I live in South Florida so don't stay in many of the hotels as you can imagine). It gets very good reviews.
The Marriott Harbour Beach is what Carole is thinking about. It is a wonderful resort with an outstanding seafood restruant called 30 30. The pool area is expansive and the service is top notch. A AAA rate will buy you a room from $150-$200.00 per night depending on view.
Have stayed several times at the Harbor Beach and agree it is a nice hotel, but i think its over priced. Last time i stayed , my room was in the 350-400 $ range and frankly WAY over priced for what i got.
I have never stayed there for less than 200.00 per night( yes i did shop prices for the property)....(i did want ocean view or at leatr partial ocean view)....best of luck.