In reply to flash13:
Marinaio di Foresta (6a+) is amazing and not to be missed! 7 pitches of fantastic albeit very sharp climbing on an iconic sea pinnacle.
The Sound of Silence (5c) as others have mentioned has some superb climbing and is in a beautiful valley, although might be a bit easy if you are looking at 6a and up, but there are some other good routes in the area which are a bit harder.
Lughe 'e Vida Mia (6a) is worth it for the adventurous approach (if you like that sort of thing) through the incredible Golo Su Gorruppu gorge. The climbing isn't that amazing, but the situation and location of the route made it very memorable. (If you climb in the gorge you need to register with them in advance so they know you are there, we got into trouble for not doing so!)
Compagni di Viaggio (6a+) was also very good, although I think there are some slightly harder classics on Monte Oddeu if you are climbing up to 7a.
