Smoo Cave, just a 5-10 minute walk from the centre of Durness is an amazing experience. The cave itself houses an 80 foot underground water fall that is apparently an amazing sight (although it rained heavily when i was there and approaching the view point was like walking into a power shower) with a defening noise.  The estuary of the cave provides a most stunning view comparable to images of unspoilt New Zealand.  Also the path to the right of the cave going up to the headland, although slightly dangerous in one partciular place provides more incredible scenery.  If you like peace and quite in a beautiful and remote setting, and don't mind too much about the weather i'd reccomend this place out of season.  Don't expect too much snow though as the salinity of the North Atlantic means you genrally have to venture further in land for the white stuff.