Marciana Marina itself is a touristy town. We had an splendid last-night-in-Elba meal at the Trattoria Secco in the main square - and couldn't decide between there and the Quattro Rioni in Capoliveri as the best eatery we visited. You will just have to visit both and make your own minds up.
We earned the meal by a longish hike across the hills to the tiny hamlet of La Cala. This appears to be only accessible on foot (or donkey), though the maps show a road winding higher up in the foothills of La Capanne. The picture above shows the village from the sea (taken the next day) amidst the thick greenery We trekked through beautiful woodland, reminiscent of New Zealand (and, inevitably, Middle Earth), hearing doves and cuckoos and filling our water bottle from a fresh stream of mountain water.
It was about 90 minutes each way. La Cala is half way to the small settlement of San Andrea, but we couldn't see any easy way to fit with the bus timetable, so retraced our steps. It was as well we had taken a packed lunch as the footpath is very isolated and apart from one exclusive hotel there are no facilities along the way.