Riomaggiore is the place to be at. A couple of years ago people chilled out on the beach in the night with guitars.
also, spend one evening in Vernazza, it is very romantical, Riomaggiore is romantical too but Vernazza is the top (it´s also more expensive than Rio)
You will love it.. its the most wonderful atmosphere, you really feel the little village, they have left it in its original state. no cars and all (you have to park them in the hills)
I don´t remember how the restaurant was called.. but you really cant miss it, you go down the stairs to the porto/ beach, just when you went down you pass a small tunnel, there´s (or there was) a diving school; just 20 metres after that you go down another few stairs to the port, and just at these stairs, at your right side, you will find the restaurant; you can also sit outside and watch the sun go down for dinner, or you can take a place inside, its a rather small place. And you should reseve it in the afternoon, if you want to go there in the evening; or for special italian festivities (15th of august for example) you should reseve 2, 3 days before.. you have to say
voglio riservare una tavola per questa sera (domani sera) per due (tre,..) persone
oh yes and you should see if you can find the secret beach.. once you could access it through a train tunnel, last time i was there the tunnel was closed, up there is a camping place.. actually the only place where they also have nude bathing.. its not allowed in italy.. but it could be that the beach is closed now, they had problems with the campers there,.. when you get out of the train in corniglia, the third of the five villages, you walk from the station to the train tunnel -
plus, don´t miss the via dell´amore.. perfect for honeymooners in fact.. mhm yeah, i have left a message there, some lyrics by Prince.. and my ex left some lyrics by U2 (One) in one of the windows at the via dell amore ... they will be bleached out by now