Slieve Binnian is so often overlooked, but it's a classic. The route from the Silent Valley is my favourite. The sight of the eerie rock formations looming out of the mist or the great views across the Mournes and out to sea on a clear day all add up to make it one to do. The ridge itself gives access into the centre of the range, so you can make your day as long or as short as you wish.
(Written by: hutch952)