Kynance is beautiful, Sennen too. St Ives has a lovely beach and the town is really quaint and interesting - but busy - and I think the accommodation is more expensive there.
Many years ago we stayed in a self-catering cottage in Botallack, near St Just. (I believe that is where Poldark was filmed). It was very atmospheric and quite different. It was a lovely holiday. Quite "brooding" and dramatic in misty/rainy weather though.
Fowey is a very attractive and interesting town with lots of nice shops and places to eat, and set on the estuary.
Last year we went as a family to Newquay. Our son and his partner and their son stayed on a really lovely caravan site - Hendra - on the outskirts of Newquay in a good setting. I would recommend the site. It was very clean and attractive with good facilities, and they had a spacious caravan with two WC/shower rooms. My husband and I stayed, with our granddaughter, in a really nice flat with a fabulous view, in the Pentire area. Newquay has some lovely beaches - we especially liked Crantock. On the down side, we thought Newquay town was a bit "rough" (has some stag and hen dos) - tatty - lots of litter - and we had difficulty finding anywhere in the area that served good food.