I just read a mention that the Riu Cancun was the tallest. It's a very nice hotel, as well. Check out the other thread I'm posting just now with that TR...
... And what about best LAGOON view? I want to be high up.. but I don't know quite sure exactly what I want. Carisa and Palma were too small for me this year Nicky
The Annex building is a separate six story building of the RIU Cancun which resides directly over the pool areas. These rooms have large private balconies with incredible view of the Caribbean looking towards Isla Mujeres.
Unless I am completely mistaken, I believe the rooms in the annex building at Riu Cancun are considered to be suites, therefore be sure to look for that option when booking. 212eric