Malin Head (of the "and finally" for shipping forecasts devotees) - went there many years ago and thought it was very beautiful and rugged scenery. If you don't want to visit Derry/Londonderry (although we thought it was worth doing) you can take a ferry across Lough Foyle to reach the area. When we visited many, many years ago the ferry had just started up and was extremely busy with cars from NI going to the Republic to buy petrol! You can take your bike over to Rathlin Island in summer if seabord watching is your thing - I remember them being very impressive.